I'm late to this, but I'm doubtful that that perception is correct. It's true there are fluctuations, as with anything on HN, but the baseline is pretty stable. But the perception that HN has gotten-more-political-lately is about as old as the site itself. In fact, it's so common that about 8 years ago I took a couple hours to track down the history of it: https://news.ycombinator.com/item?id=17014869.