According to Fan Dumb, Sakura is stupid for not leaving her "love rival" Hinata to die. LOLWAT.note Most people, Fan Dumb or not, tend to forget that even if Hinata did die, Pain would've revived her alongside the rest of the village, anyway.
Surprisingly, she hasn't gotten much more hate than usual with Chapter 631. The hate is directed towards two other people actually: Minato and Naruto. See below.
An even more extreme case is Karin, Sasuke's new teammate, who gets bashed from both SasuSaku andSasuNaru fans, although the former are more virulent about it. Fans often make Karin into an oversexed nympho with constantly opened legs (when she's almost the exact opposite) who tries so hard to "steal Sasuke from his rightful lover Sakura and/or Naruto", especially if the fic's setting is High School. True, Karin's infatuation with Sasuke wasunhealthy and obsessive — However, the shippers' attitude towards her still carries a whiff of this trope, since they ignore that most of her antics are Played for Laughs and as more of a character flaw than a marker of being "a bad person", that Sasuke knew about all this when he recruited her for his team, and that beyond this she does genuinely care for him.
There's a fair amount regarding the Ino/Shikamaru/Temari triangle. Shika/Tema fans often turn Ino into a shallow and shrill bimbo who only thinks of her looks and is way too stupid for Shikamaru. Shika/Ino fans often bash Temari by making her a domineering and cruel Yandere-bitch who stops at nothing to make Shikamaru hers. Things got worse when another girl named Shiho took a romantic interest in Shikamaru, becoming the triangle's Third-Option Love Interest; both Shikamaru/Temari and Shikamaru/Ino fans want her to die in a fire.
Hinata Hyuga is bashed a lot for liking Naruto or (according to some fans) her cousin Neji. There are several fics where Hinata finds out that Naruto has the Kyuubi trapped inside him and proceeds to hate or fear him, only to be slapped into shape by Sakura. (The idea was Jossed in Ch. 355-356, when she doesn't react when it's mentioned around her). There's also the hate she receives for her characterization as a Shrinking Violet with such fans saying that "she's too weak and shy and doesn't deserve Naruto". Naruto/Hinata and Naruto/Sakura pairing wars get ugly; it's always assumed that Naruto/Hinata fans bash Sakura (a majority of them don't), and Naruto/Sakura fans bash Hinata (again, a majority of them don't).
Has become specially ugly since Naruto saved Hinata's life in the middle of the Shinobi War and has aknowledged her as a strong person. The Sasuke/Naruto shippers on several places (specially tumblr) have gone berserk at that, pouring tons o shit on poor Hinata and the Naru/Hina shippers. Said fans are also often unhappy that Hinata was the one who got Naruto out of his Heroic BSOD caused by Neji's death.
Shino is badly treated in the few fics about Kiba/Hinata. This is odd because Shino seems to have no romantic designs on Hinata at all.
It's bad enough that so many characters are treated to Die for Our Ship in favor of the virtually asexual and very troubled Sasuke, but the equally virtually asexual Shino is treated to this for a ship on a much more minor scale… seriously. If there was something called shipping dissonance, the Naruto fandom would have it covered.
Many yaoi fangirls tend to to pair Kiba with Hinata at first only for him to realise in the end that she is a manipulative bitch and have him fall in love with Shino or another male character in the end.
Kiba often gets characterized as easily jealous and overprotective of Hinata.
Kiba may just be the most bashed male in the series after Sasuke
Neji is sometimes treated poorly in fanfics that pair Hinata with someone else (especially if that someone else isn't Naruto), and he is sometimes portrayed as hating Hinata even after his Heel-Face Turn. Oddly, Neji rarely suffers in Tenten/Lee ships.
Even minor characters get it. Matsuri appeared as one of two Gaara fangirls in the manga. In a Filler arc of the anime, she had the misfortune of being introduced as the only one willing to accept Gaara as her teacher during a training session. Raging fangirls hate her guts because of the possible Hot for Student-like Ship Tease moments she had with Gaara, something NO other girl on the show ever had. This page shows just how far Fan Dumb can go...
Then there are the Unfortunate Implications that these Gaara "fans" want the only person (besides his siblings, Naruto, and maybe his mentor) that would give him a chance to die. Apparently, they want Gaara to have more reasons to morbidly depressed, lonely, and suicidal. Let the guy have a companion, people. He really needs it.
Sai not only gets criticism from Shika/Ino shippers, but also gets lots of flak from Naru/Hina shippers for telling Sakura how much Naruto loves her, even though it's shown later that he's no Shipper on Deck.
It doesn't help that he was emotionally repressed and he feel into total stoic mode because the only person he cared for like a brother died. He reads books on relationships and love because he can't understand it by himself. In the real world, he would have to undergo intense therapy (actually a lot of characters need to). Then there are the fan fics that depict him reading porn that makes him decide to capture a female cast member and try it out on top of the fact he doesn't know sexual assault is wrong, effectively calling him an ignorant rapist. This is despite the fact that he must already know what sex is because we see him insult Naruto by stating that his "package" must be small. That just indicates that he probably knows what "packages" are for and why it is an insult in the first place.
Asuma, who along with Kurenai was part of a rare official couple in Naruto, gets treated poorly in some fics that pair that her with Kakashi or someone else.
Sasuke gets this sometimes, too, which is only natural given what a Base Breaker he is - it's not too hard to find people that don't want him anywhere near their preferred girl/couple. This is mostly Naru/Saku shippers - which gives them an opportunity to have Sakura realise how much better Naruto would be as a partner (at least when they don't exaggerate it) - but some others who are protective of their favourite characters take extra care Sasuke won't dare interfere. Fact is, though, in Fan Fiction it's actually not that hard to take Sasuke's negative traits Up to Eleven with a little work, making him a villain handily enough without making him unrecognisable... that is, if they don't just kill him outright (seriously, some writers have even written Wave-AU-Fics where Sasuke is killed by Haku, an incident he survived in canon).
It's true. He gets turned into a far more horrid individual in so many fanfictions its rare to find one where he isn't a complete monster.
Rin, the Combat Medic in training that was in a Power Trio with Kakashi and Obito in the past, got quite a bit of snorts and bashing from fans because of the Love Triangle: Obito liked her, Rin liked Kakashi instead, and Kakashi felt that he couldn't return her feelings after Obito's death. The heat, however, has started to take quite a bit of misogyny-based force after a recent chapter revealed that Obito grew into the very shady and evil Tobi from the Akatsuki as a result of a chain of events that started with his apparent demise, and included Rin's death, which the Fan Dumb intepreted as her being at fault for Obito's Face-Heel Turn and then "translated" into "Fucking bitch, she didn't give Obito vagina, now he's evil. IT'S HER FAULT"
Minato is officially public enemy #1 in most Naruto/Hinata fans' eyes for asking Sakura if she was Naruto's girlfriend, comparing her to his wife Kushina and asking her taking care of his son. Most wished he hadn't said anything at all when they are not calling him an idiot who "doesn't know anything about Naruto or Sakura". Apparently not knowing anything means he can't ask questions and take the answers he gets at face value.
Naruto gets it almost as bad as Sakura and worse than Sasuke. Sasuke/Sakura fans or Sakura/anyone else fans already see him as an obstacle. But what's really surprising is now Naruto/Hinata fans are giving him this treatment. In chapter 631 he told his father he considers Sakura his girlfriend("more or less"). He has been called every name in the insult book because of this and now a good chunk the of Naruto/Hinata fanbase wish for his head on a platter (or at least for Hinata to slap him or something.)
Fics that pair Hinata with someone other than Naruto tend to have to explain at some point why she is not pursuing or with him. Some may indicate that Hinata decided that she wasn't actually in love with Naruto, but others kill Naruto off or have him reject her in favor of Sakura without any regard for her feelings.