Nitpicking like the question whether "his or her" or "their" is better und using a link that on first sight doesn't seem to have to do anything with the used words? Correcting, ok! But not schoolmarmish like that, ok? Besides: In the above context "his or her" is more polite considering mistakes maken by single persons. I am no "they".
Last but not least, I don't want people to read through linguistic instructions for reconsidering such vanities. If you have something to insist, do it directly and obvious. Don't just throw a non-saying link in and let people stay in the cold.
No use in pointing it out either. Why not let the whelps have a little trial and error? Where's the difference in raping one's mother language or another? My eyes already have been burned out looooong ago.