In YuYu Hakusho, two sadist teachers badmouth Yusuke at his funeral and even suggest that Yusuke pushed the kid he saved into the street in the first place. Another teacher, the one who believed Yusuke had potential, calls them out on it.
A defining characteristic of Bleach's Yhwach is that he will often insult and belittle dead enemies (or allies) to the proverbial faces of their corpses. Then, there's the time he killed Yamamoto whom he *really* didn't like... he then proceeded to deliver a poignant Reason You Suck Speech and proceeded to desecrate his corpse by hacking off his one remaining arm, stomping on his head, and completely incinerating the rest.
Naruto: Not exactly speaking ill of the dead, but the basic principle is the same: when Gato arrives on the scene after Haku's death, one of the first things he does is kick Haku's body in the face as payback for Haku breaking his arm and wish that Haku was still alive to feel the hit. It makes his Karmic Death at Zabuza's hands all the more satisfying to watch.
In Reid Fleming, World's Toughest Milkman, Reid pretends to have been stabbed in the back on the doorstep of a couple of his customers, to freak them out. Not only are they overjoyed that he's (apparently) dead, but when the mailman happens by and sees the body, he congratulates the couple, and runs off to tell others the good news!
In Runaways, Molly Hayes drops her "Rudy Huxtable" routine when the time displaced Geoffrey Wilder calls her out on it. She then coldly mocks Alex Wilder Geoffrey's son murdered by the Gibborim for his failure and calls him "a total frikkin' failure."
In Team8, Kurenai fairly harshly says that if ninja on reconnaissance missions get into needless fights and die, they are "fools" and don't deserve to have their names on the memorial stone.
From A Christmas Carol — when Scrooge is visited by the Ghost of Christmas Future, he sees many people stealing from a dead man, laughing at how much better things are without him, and telling nasty stories. He's horrified to find that person was him, and that no one genuinely misses him.
Break of Dark: When they shoot down the German pilot in Blackham's Wimpy, Blackham and his crew not only spend the next 20-30 minutes exulting and mocking him as he burns to death, but carry on their celebrations when they get back to base. Strongly implied that this is why he comes back to haunt them.
In The Hunger Games, Clove intentionally mocks Rue's death while pinning Katniss down at her mercy. However if she didn't chose to rant and kill Katniss right there, Thresh would have never overheard and killed Clove for saying such things.
In Harry Potter, Hermione speaks ill of Sirius, about a year after Sirius' death: "Sirius was horrible to Kreacher... I've said all along that wizards would pay for how they treat house elves. Well, Voldemort did... and so did Sirius."
In the Sherlock Holmes story "The Adventure of Black Peter", the titular Asshole Victim suffers from this; his own daughter flat-out tells Holmes and Watson that she's glad her father is dead and blesses the hand that killed him.
Live Action TV
Game of Thrones: Queen Cersei and King Joffrey have no qualms posthumously calling the late Lord Renly Baratheon a "degenerate" in "Dark Wings, Dark Words."
In Smallville, when Lionel died, even the usual Nice Girl Chloe isn't too sorry about it. Justified because he had a strike force with kryptonite tasers to capture the love of her life and trap him in an adjustable kryptonite cage just two episodes before.
Victor Lewis-Smith's Honest Obituaries series of sketches about UK Celebrities (all of whom were alive at the time the series was written) on the short-running UK comedy series TV Offal.
After Michael Cambias' death, everyone in Pine Valley goes to his funeral just to give eulogies about how much they hate his guts for what he did to Bianca, with Bianca's lover Lena going so far as to spit on his grave.
Also, after David Hayward's apparent death, only Greenlee, Krystal, and Marissa go to his funeral, while everyone else in town throws a party to celebrate his demise.
In a famous episode of The Fresh Prince of Bel-Air, Uncle Phil's Jerkass former mentor-turned-political opponentnote Played by Sherman Helmsley dies after Will chews him out for being so rotten. At the funeral, basically nobody has anything nice to say about the man, and most showed up just to make sure he was really dead. Will, still feeling guilty, berates them by saying he might not have been a pleasant man, but he still deserves a little dignity in death. When asked who he is, Will responds "I'm the dude who killed him"...and gets a standing ovation. "Tough crowd" indeed.
On the song Reagan, Killer Mike ends the song with the line "I'll leave you with four words: I'm glad Reagan dead."
In Ajax, Agamemnon and Menelaus have good reason to hate Ajax after his attempted slaughter of their army, but veer a little too close to religious blasphemy in denying Ajax burial rights after he has committed suicide. Odysseus in comparison gives up his grudge and persuades them not to violate sacred rites.
Subverted in Julius Caesar. Anthony's speech sounds like it's going to be this ("I come to bury Caesar, not to praise him") but by clever twisting of his words he turns the assembled people against Caesar's killers.
In World of Warcraft, Varian gets upset when Anduin says the recently deceased Magni convinced himself that Moira was brainwashed to avoid having to admit that his desire for a male heir drove her to the Dark Iron Dwarves. Anduin, unlike most of the characters on this page, respects Magni, but believes that "You can be an honorable man and still make mistakes."
After one of your True Companions from SEES dies in Persona 3, the school holds a memorial service. During this, you overhear some of the students talking bad about the recently deceased, and can choose to confront them.
In Saints Row 2, Shogo attacks Aisha's funeral as Johnny Gat wants a moment to bury her in peace so he can personally fight with him. Shogo disregards that and gets buried alive for his trouble.
In Ace Attorney Investigations, Manfred Von Karma calls Byrne Faraday incompetent as a prosecutor before and after finding out that he's been murdered. In the sequel, Manosuke Naito insults his dead fellow bodyguard Gai Tojiro in the first case, and everyone else is horrified. Naito also turns out to be Tojiro's murderer.
From Justice for All, we have Dr. Turner Grey, who, a few years ago, lost a large number of patients at his hospital, and blamed nurse Mimi Miney over it. The same night, Mimi was killed in a car accident (or rather, Ini; Mimi underwent facial reconstruction surgery and took on a new life impersonating Ini). Turner doesn't think any higher of Mimi despite her death and seeks out spirit channeling so he can force Mimi's soul to confess to her misdeeds. Unfortunately for him, he's murdered shortly thereafter by Mimi herself.
Resident Evil 6 features two examples in regards to the late Albert Wesker:
When she first meets Jake in Edonia, Carla has absolutely zero qualms against referring to Wesker as a "colossal imbecile" and a "fool." While talking to Wesker's own son, no less.
Later, after Chris and Jake's confrontation near the end of their respective campaigns, Piers insists that Chris didn't have to confess to Jake because Wesker deserved to die and Chris did what he had to do to keep the world safe. Chris is quick to point out that, even after everything Wesker had done, he was still Jake's father and Jake had every right to know what happened to him.
Assassin's Creed: The Assassins make it a point to avert this, but there are exceptions. For example, after Ezio assassinates Vieri de' Pazzi, he proceeds to viciously insult Vieri's corpse, declaring that Vieri got what he deserved and he wished that he suffered more as he died. His uncle Mario steps in at that moment and urges Ezio to have more respect for the dead, warning him not to stoop to Vieri's level.
In The Order of the Stick, aside from Nale's girlfriend Sabine Elan is the only person who feels bad when Tarquin kills Nale after the latter finally pushes his luck too far. Haley and Tarquin, not so much. Haley says that Nale was a terrible human being who deserved to die. Tarquin is even harsher, coldly dismissing Nale, his own son, as nothing more than a B-villain that Elan has outgrown. Laurin Shattersmith, another old friend of Tarquin's and Malack's, merely says "good riddance" and Disintegates Nale's corpse to make him Deader Than Dead.
In Hey Arnold!, at Dino Spumoni(not dead) funeral his close friend only talked about how Dino was jerk.
The Boondocks had an episode where Moe, an old friend of Robert's who he had fallen out with passed away, and left a video will saying that he wanted Robert to deliever his eulogy. With reluctance, Robert agrees. At the funeral he's given a script Moe had prepared before hand. Robert starts reading it out, only to find out that it talks about how awesome Moe was, making Robert say that he was sexy, paid his rent numerous times and so on. Robert gets fed up, and tells the funeral goers the honest truth: that Moe was an asshole who only asked for Robert so that he could make a fool of him again. The other attendees agree that he was an asshole.