Even the sweetest and kindest of all the All-Loving Heroes (or any kind character archetype), who may have helped other villains fulfill a Heel–Face Turn and serve as Morality Chains for other characters, has people they dislike and may be one of the few things this loving hero actually hates. Often, the villain has done things that even this hero finds completely unforgivable. The hero's negative opinion allows them to serve as an Audience Surrogate. A trope that symbolizes how much a villain (which may be Ax-Crazy, Hate Sink, The Sociopath, or even a Complete Monster) is morally gone or crossed the Moral Event Horizon in a way that can't be fixed.
Villains that are targets of this trope don't tend to make Heel-Face Turns or at least be Reformed, but Not Tamed like other, more sympathetic, or reasonable villains, since even the archetypes that are known for helping that process are disgusted by them, and the most common way they get out of the plot is through death.
Occasionally, this trope can be Played for Laughs, where the otherwise Loving Hero reserves their hatred for someone who isn't really evil at all and doesn't seem to deserve it; mostly simply for extremely petty personal reasons, in which case see Sitcom Arch-Nemesis.
Sub-Trope to Everyone Has Standards and OOC Is Serious Business. An inverse of Even Evil Has Standards, where a bad guy can't bring themselves to cross some line, Even Evil Has Loved Ones, where a bad guy has someone they genuinely care for, and Even Evil Can Be Loved, when another character genuinely cares for the bad guy even if the feelings are one-sided. Compare Beware the Nice Ones, Even the Dog Is Ashamed, and Jerkass to One.
