Sometimes, not even death will curtail disrespect for one's enemies. In fact, it provides free rein to voice disapproval and disdain! This is usually a case of Last Disrespects, but sometimes it will be used to voice Brutal Honesty about issues surrounding the deceased.
The opposite of Never Speak Ill of the Dead. When this is played for laughs, it's probably putting The Fun in Funeral.
This is a Death Trope, so expect unmarked spoilers ahead.
In Yu Yu 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 Juhabach 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.
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."
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.
Live Action TV
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.
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.