[wutbrodo]

I think the idea is that the accusation of racism isn't really a concrete, well-defined concept that can be falsified: in terms of specificity, its closer to calling someone a dumbass or a butthead than it is to calling them eg a shoplifter; the former isn't legally actionable (right? Perhaps I'm wrong here), but the latter is concrete enough to be.

I'm not sure if I agree with the gp commenter, but it doesn't seem to be a particularly unreasonable opinion to hold.