XKCD. Sure. But everybody knows this, yes? And to make this point alone — it’s a pretty cheap and easy point, after all — is to avoid the questions that really matter: What kinds of differences in opinion ought to result in shunning, shaming, marginalizing, and banning? When, by contrast, is it better to tolerate differences in opinion because by doing so we enable certain social goods? How far do we want to go in excluding, whenever we have the power to do so, people with whom we disagree?