That's only the case because the guidelines and moderation practices are set up to keep political flamewars off the site. Those benefits would evaporate very quickly if HN was allowed to become a political free-for-all.

The perspective that politics shouldn't be discussed because it is difficult is the rationalization.

The difficulty of political discussion isn't the rationalisation; the rationalisation is the predictability and mundaneness, and pointless incivility; i.e., people get emotionally heated, but resolve nothing and nobody learns anything. Nobody benefits and the quality of the site only degrades.

Topics related to politics are discussed here quite successfully all the time, and when it happens it's because the topic and resulting discussion is gratifying to one's curiosity and/or evidence of some interesting new phenomenon , as per the site guidelines.

the underlying motivation for some is the desire to treat tech and the work we do as apolitical, because to do otherwise would have uncomfortable consequences.

Few people are intelligent and socially-aware enough to be a high achievers in their business or career and yet naïve enough to think that their work is apolitical. And plenty of prominent HN contributors are perfectly capable of expressing strong political positions in their tweets and blog posts but keeping them out of their comments on HN.