A Curmudgeonly Pun

Not much content in today’s post, especially since this doesn’t apply to me: I have no trouble correcting grammar. When asked.

https://www.gocomics.com/realitycheck/2018/08/21

Hmm. You might say that it should be “peoples’ grammar,” but I suspect he talks to one person at a time; justifying use of the singular. Maybe. What do you think?