If the movie's sole female protagonist had been Amy, you could be justified in thinking the movie was misogynist and preying on every bad stereotype men have of women. She pathologically uses the men she dates and then accuses them of rape or murder. But Amy wasn't the only female protagonist in the movie. The male protagonist was practically surrounded by a varied cast of female characters, each with their own personality, agendas, strengths and weaknesses. There was Affleck's sister, the female detective, the woman he was cheating with, the woman who stole from Amy, the Nancy Grace clone, the female reporter. You had such a large and varied cast of female characters that you could get away with a few nasty females like Amy and Nancy Grace clone. And why shouldn't you? Bad women exist. They're real. Stereotypical women exist. So why shouldn't an author portray them? Bad people make a story interesting. And you can get away with female stereotypes, nasty, horrible women, much more easily, if you have a varied cast of females who are individuals in their own right.
I know some feminists think the movie was misogynist, but I disagree, and I know some other female feminists agree with me. I felt the movie was great for women, because there were so many individual and well developed female characters. You had an interesting story because you had the liberty of exploring dark subjects, a liberty provided to you by the sheer quantity of well developed characters. You can get away with having a character who's a stereotype, if you have others who aren't. You can easily destroy tokenization, by increasing the amount of characters you use.
Similarly, the more LGBT characters you have, the easier it is to avoid misrepresentation, because you're able to show the bad, the good, and everything in between.