The Killer Grips in "The Chefshank Redemption". They're seen as being in the right for forcing Gwen into throwing the challenge for her team and subsequently eliminating herself as blackmail for how Trent would keep throwing challenges for his team to keep her safe... Even though she had no idea that he was doing so in the first place.
Cody in World Tour. While Sierra's treatment of him does crosses many lines, some felt he was hypocritical for his continued obsession with Gwen, even after she and Duncan hook up. That said, Cody’s behavior towards Gwen is nowhere near as dangerous and disturbing as Sierra’s treatment of Cody.
Duncan,, while the show doesn't try to hide the fact he's a bully, he keeps getting treated by others as the good guy up against the real villain. Particularly prevalent in All-Stars where there's his In-UniverseVillain Decay leading to everyone (especially Chris) who keeps hailing him as a hero.
Chris deemed Gwen a villain in season five for the sin of "stealing" her friend's boyfriend yet ignored the actions of most of the original line up of the Heroic Hamsters:
Regardless that she is manipulated by Heather to do so, Lindsay still went along with her to ruin Gwen's relationship with Trent in season one, which is only one of the many things she did during their alliance. That the others never reprimanded her for siding with Heather for most of the season and only sees her as an unwilling accomplice makes her elimination a rather mild punishment.
Courtney's already a rude person to begin with and has shown to be willing to do anything to win, from betraying her own boyfriend or dropping several contestants from a hot-air balloon. It's small wonder that she is eventually transfer over to the other team.
While Sierra is a nice person at times, her obsession with Cody and the rest of the cast makes her seem ill-suited to the title of "hero", and she rarely shows said niceness to anyone who isn't Cody and her violent tendencies are rather extreme, having the intention to kill Heather in one episode with a drill.
Mike seems to have absolutely no problems with keeping damaging secrets from others, only to hurt them even more when he reveals them.
While Shawn is treated as one of the main heroic contestants of Pahkitew Island, some feel that he comes off as a Designated Hero due to his zombie schtick getting old very fast and making him occasionally very selfish and cowardly or excessively paranoid, as well as him being partially at fault for ruining his relationship with Jasmine, and being extremely reluctant to split the million dollars with her. While he did eventually do the right thing, made up with Jasmine, and split his winnings with her, he made things harder than they should have been.
Sky from the same season falls into this boat too because of how harshly she treats Dave late in the season, her overly competitive nature coming off as largely unjustified, and her moments of hypocrisy earning her negative comparisons to Courtney. It doesn't help that many have also drawn negative parallels with Zoey.
Emma in Island (2023) is supposed to come across as a sympathetic Nice Girl. However, her obsessive Jerkass to One attitude towards Chase (who, while deserving of it, often makes Emma look extremely petty and childish), her getting back with him despite multiple red flags and warnings from other contestants, and her Ungrateful Bitch attitude towards her former best friend Bowie once she learns he voted for Chase can severely overshadow her more endearing qualities in the eyes of fans.
