It's refreshing when a responder is frank about their own political preferences, since the point in these disputes so often comes down to some political issue, some point of status. It also makes the argument easier to puncture, viz., singular they has been current since the time of Chaucer, who was evidently little influenced by Betty Friedan. Or that the speech of illiterates does work bottom-up in the language, which is how we got from Anglo-Saxon to modern English. As with individual stylistic preferences, people are entitled to hold political views. Or that sensitivity to sexism and other "politically correct" issues has become a component of public manners rather than an imposition by a cabal. As with individual stylistic preferences, people are entitled to hold political views. But changes in language usage are normal, and they do not endanger civilization.
8. But the sticklers will complain.