Obviously, I disagree with many things about the approach HN has taken, but of course it is your site, you can do as you want.
For starters, if you say people can just skip things that don't satisfy their curiosity, I don't see why the same wouldn't apply to political controversies. I can understand if you want to moderate the "root articles" (the once that are listed on the homepage), but why do you care about the comments? If people discuss something, obviously it interests them (strikes their curiosity). What does it matter if they make a 10000 comment thread about it? I think you have some sort of algorithmic counter measures against long threads, which does nothing but enrage (presumably based on some heuristic PG once made, when he felt long comment threads signal flame wars)
Ultimately it seems to me all about the people you attract here to vote on things. I've just tried to read that article about Atwood, and it is entirely too long-winded for me. If HN had been founded by some famous literary professor, you would probably get only submissions like that, and nothing about technology or science. But it was founded by PG and now it is associated with YCombinator, so it draws a different crowd.
Just saying I don't think the "curiosity" rule is really what makes HN, it is the people you manage to attract.
And to that I personally can say, I wouldn't mind some other user ripping into me in comments for some political or other reasons. I do mind HN itself telling me I am not wanted here , which it does in so many ways.
Of course, again, that is your right to do, as it is your site. It just makes me sad (unsurprisingly), having been on HN since the early days. And ultimately it does seem to boil down to political opinions, even if you don't consciously target certain opinions above others, as you claim.
Since the value of HN is its community, we have to regulate the comments carefully. The main tool for doing that is https://news.ycombinator.com/newsguidelines.html. Not to do so would cause HN to suffer the default fate of internet communities, which tend eventually to become burnt-out husks of their former selves. The idea here is to stave that off for as long as we can: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu....
That's why we keep asking you to follow the site guidelines. It's not just because your individual comments get better when you do that. It's also because the feedback loops involved (the effects of comment quality on the community) are large and existential for HN.