If you like a villain, you have to be gunning for them to get a redemption arc and for them to have some reason that excuses their villainy. If someone doesn’t like the character you like you must prove that they are Wrong about your precious character.
And especially if a Big Name Fan says they have a negative opinion of a character, that character’s fans seem to have a need to dogpile the BNF. Or maybe they’re not a BNF, maybe they’re someone involved in the work itself.
This shit makes for reductive and vitriolic discussions, stymies interesting analysis, is toxic to the fandom as a whole, and is plain not healthy to the people acting as “white knights” for fucking fictional characters.