If people made a new adaptation of Lolita, the image of a man's shadow looming over a child in lingerie and a come-hither pose would still evoke Bad Things even if Humbert Humbert is the bad guy and Lolita's shown from his deluded perspective. If people made a movie where the villain's a white supremacist, the sight of a black guy getting lynched in a movie poster for shock value would still strike some pretty sore spots regardless of the villainousness (villainity?) of the white supremacist. "But he's the bad guy" doesn't erase the contextual and societal bad karma some imagery has. WoTC realized this with their Magic: The Gathering card
Triumph of Ferocity after feedback, and so they made
alternate art for it in a reprint.
SCarpe probably said it better than I did, but eh, I felt like chiming in.