It isn't that we "can't talk on here", it's that threads are flameprone and vulnerable to initial conditions. If the initial condition is, say, a cheap swipe with 'fascist', the discussion is likely to flare into ideological battle. That gets the blood pumping but otherwise benefits no one. Overheated political rhetoric, such as your comment contains, isn't much better. All it generates is more of the same, from people who either share your feelings or don't. None of that is in keeping with either the spirit of this site or its rules (https://news.ycombinator.com/newsguidelines.html), so it's off topic here.

What initial conditions make for good discussion? Two things: first, a substantive article that contains information rather than just rhetoric. Flamey rhetoric is a sugar high and our minds need something to chew on. Second, initial comments that earnestly engage with the information in the article (as opposed to potshots or pre-existing talking points). When those things are present, politicized topics can be ok for Hacker News. They can still degenerate into flamewars, though, in which case they become off topic again.

Edit: dismayingly, it looks like you've been using HN primarily for ideological battle, which violates the site guidelines, and gotten nasty in the process, such as https://news.ycombinator.com/item?id=17323529 and https://news.ycombinator.com/item?id=17323169, which I probably would have banned you for had I seen it. We ban accounts that do these things, for the same reason: it degrades the site well below the level needed for not going up in flames. Would you please stop using HN this way?

All of this stuff is important, it's just not the topic of this forum.

I'm a Canadian, so no to your 5th question.