When did the term “ cancel  culture” become a thing?

A few weeks back.  Do try to keep up.  Everyone's saying it now.

You're just too far behind to catch up, at this point.  Why not just avoid saying it for another few weeks and then it'll be gone?  Then you'll be all ready to grab onto the next big thing early on!

My bet is that if you say it in September, everyone will turn to look at you, and say "OK, boomer".

(The bonus to this plan is that, in addition to not having to add it to your vocabulary just in time for it to become passé, you ALSO get to not LISTEN to it.  Anytime you hear some talking head jabbering about "cancel culture", just tune out.  You won't miss anything, and you'll feel much happier.)

When people found they didn't like being told off / having  consequences for their words and behaviour