You forgot option 3: telling them to shut up, sit down, and get back to the lesson at hand.  No one is reading TKAM and saying "and so you see, clearly the nigger is subhuman trash, fit only to fertilize our fields like the excrement that they are". They're saying "Wow, holy shit, that girl is insane and those people are racist as fuck, holy crap. Thank goodness Atticus has at least a modicum of decency and does his fucking job".  It's literally anti-racist, pro equality. Fuck, I hear more people yelling nigger on the radio when some "greatest hit" from some shitty rapper comes on in a few sentences then you hear in this entire novel.