Yes, much political discourse on HN tends to be lower quality.
However, trying to establish HN as a "politics-free zone" is not only impossible but deeply problematic when so many of us work on things that are politically important. (I'm trying to avoid rehashing the whole article's argument again here.)
Getting your diet of political discourse somewhere else effectively means staying in your ideological filter bubble when you talk about politics. The political discussions here are valuable precisely because we can't do that here; HN members are self-selected by interests that cross-cut political lines.
The perspective that politics shouldn't be discussed because it is difficult is the rationalization, and 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.