It's because there is extremism both on the left and right: the left thinks that the right wants a power grab to stop left from coming back, and the right thinks that if they don't keep their power now, the left will take it and keep it using immigrants.

Both of them are right: unless there's a civil war or moderate president (which probably needs ranked choice voting) the most probable scenario is that one of the 2 extremes succeeds.

I also miss the old HN btw and wish that there wouldn't be any right/left politics, just the old classic libertarian property/privacy/opennes right debates, but it looks like those days are gone.