They could also write the comment in French, and by the same argument people should need to go out of their way to copy-paste that into google translate.

Thousands of people are going to read this thing. The writer could spare thousands of people spending tens of seconds (totaling days of human life), by simply spending less than a second spelling out the obscure term.

Who's going all the way to Google translate to copy and paste? You just select the text and right click/long press and select translate.

I'm not sure what you are attempting to add by being pedantic while not affecting the conclusion in any what whatsoever.

Boy are you going to be surprised when you find out that there is an entire French literary tradition that doesn't concern itself with who does and does not speak the language.

Is this some snarky reddit comment?

Yeah, there are literally billions of people in the world who don't speak English. And yet HN is de facto English.

Do you see many people commenting on HN in French? How's that working out for them? Are they succeeding or failing to communicate?

It seems that people are, for the most part, succeeding in tailoring their message for their audience.