I'm asking the same myself. But we all know the answer. HN is a dictatorial space that uses censorship to unify its opinion in a liberal banner. If you have progressive ideas you are out of the club.
That's not true! lots of people here have progressive ideas. Lots of people on the other sides, too, of course. The community is divided because society is divided.
It is true that the political battle style of comment tends to get flagged and downvoted, because it's bad for the intellectual curiosity that HN exists for. But it's still possible to have thoughtful conversation about such ideas; it just unfortunately tends to degenerate quickly into not-so-thoughtful.
[EDIT: why the downvotes, again?]