Privacy shouldn't require leaving your PC running 24/7.

I think they were being sarcastic. It's too stupid a comment otherwise.

It’s not that stupid, I think many PC gamers do exactly this, including me.

Still, it’s a bug that should be fixed.

Yes in that case there would be no data transmitted, and no risk.

Another example: if the user turns off "Turn on when Windows starts up" or whatever equivalent, this would also be a non-issue.

Not true - if users want to play a game without appearing online, this would still out them.