Seems to me that if you say something racist/sexist/homophobic/transphobic/etc, then there are a couple possibilities.
Either (a) you meant it or (b) you didn't mean it. If (b), a gentle nudge from a Hacker School pal is good, in the same sense of a friend telling me my fly is open. If (a), well, fuck you.
Or (c) what the other person claims to be racist/sexist/homophobic/transphobic/etc. isn't, at all, and this is simply the other person's way of "Well, actually."'ing you, except not even pedantically, but completely baselessly.
Either (a) you meant it or (b) you didn't mean it. If (b), a gentle nudge from a Hacker School pal is good, in the same sense of a friend telling me my fly is open. If (a), well, fuck you.