Yeah, she's a racist, and she's probably the closest thing this story has to an antagonist.
But how do you write a racist? Beyond portraying a bigoted attitude, snide remarks, inappropriate and lengthy glaring, and a sketch of her particular beliefs, how else can I show her exhibiting her particular ideas? Part of the work I have to put in on this third draft is making Mrs. Hamilton's role bigger, rounding her out. She's not a viewpoint character, so that's an added challenge to getting her across the page.