It's not exclusively (or mostly) U.S.A. residents who complain about contemporary politics topics getting flagged. We see plenty of complaints from Europe and elsewhere.
We've long accepted that there is a large overlap between politics and technology. The Snowden leaks in 2013 were huge on HN, as were several other Wikileaks releases well before that.
HN has never been a politics-free zone. It’s just subject to the same standard as everything else on HN: there has to be some “significant new information” to the story.