The unhealthy part in both cases is the inability of erstwhile professional adults to have a civil and productive conversation about things that matter, and like as not, politics does matter. It matters a lot more than many of the topics that get discussed here, despite being sorted into the "mainstream, therefore off topic" bucket by most.
It's particularly unhealthy in HN's case because this community has the pretense of holding itself to a standard of intellectual merit and civility above the internet mainstream. We can have intellectually stimulating discussions about compiler design or type theory all day long but wander outside the "technical" box and suddenly people are screaming about white genocide and cultural marxism or spouting QAnon or anti-vaxx conspiracy theories.
It's particularly unhealthy in HN's case because this community has the pretense of holding itself to a standard of intellectual merit and civility above the internet mainstream. We can have intellectually stimulating discussions about compiler design or type theory all day long but wander outside the "technical" box and suddenly people are screaming about white genocide and cultural marxism or spouting QAnon or anti-vaxx conspiracy theories.