I asked what you wanted to know, but reading this response, it doesn't seem like you want to know things so much as to fulminate against HN and how it is moderated. I'm sorry you don't like it, and if I saw a path from here to maybe getting you to like it better, I'd be happy to try. But I'm not seeing that yet. It takes a ton of time and energy to answer posts like this, and that investment only makes sense when there's a visible modicum of good faith to begin with—otherwise it just results in twice as much fulmination, which helps nothing, and takes resources away from helping other users.
I can take a crack at replying to your question about those specific comments though. A comment that said only "We live at the absolute _extreme_ of capital power over labor power" would be lame and unsubstantive, but https://news.ycombinator.com/item?id=21983921 went on to say other things that made for a thoughtful comment, though the generic ideological topic (unions-good-or-bad) is a bad one for HN. I don't see why we would moderate a comment like that.
The reply "No we don't, that is called slavery." is lame and pedantic, but I wouldn't call it flamebait. That is the contrarian dynamic which can't resist pointing out a logical flaw in something somebody said. HN has this all over the place, as does everywhere else ("someone is wrong on the internet"...) They are low-quality comments but they don't typically start flamewars unless there is some other baity element in there.
You, on the other hand, have been posting obviously flamebaity and ideological battle comments as well as fuming about "groupthink" and "wrongthink" and downvoting and how awful everything here is. You might find HN less "impossible to contribute to" if you took its intended spirit to heart. You could start with trying for thoughtful conversation and assuming good faith, as well as the rest of what https://news.ycombinator.com/newsguidelines.html ask.