There are plenty of places you can find polite political discourse on Reddit, like these:
/r/PoliticalDiscussion/ <-- the only one I sub. /r/PoliticalOpinions /r/Ask_Politics /r/NeutralPolitics /r/ChangeMyView /r/GeoPolitics /r/WorldEvents /r/PoliticalScience /r/Economics /r/Politics
And for logical, not emotional political debates:
/r/AskAConservative /r/AskALiberal /r/DebateCommunism /r/DebateFascism /r/LibertarianDebates /r/DebateAnarchism
I’d give you echo chamber, but also point out that applies to most subreddits in your list, but especially to the ask_$ideology types. People celebrating their political wins isn’t trolling, neither is celebrating the losses of the other side. It might be many things, but posting to get a rise isn’t it.
It doesn't even make sense - people posting in their own communities about their own ideologies doesn't meet the definition either. Who would they be trolling, themselves? Oncomers who don't agree? If the latter, that applies to every political community everywhere.
That opinion, and the constant shouting of it from every rooftop and constant silencing and badgering those who think otherwise, is the reason for the existence of the_donald.
This very thread has someone in it who called me a liar because I posted an image that proves botted content on the front page of /r/politics, and then I had to spend half an hour screwing around with google to debunk it. That is the online reality for anyone who doesn't viscerally hate the president, and it's become very tiresome.
But unless you’re going to say racism, bigotry, and all the rest that The Donald/alt-right bring to the table are conservative ideals I don’t see ANY way you could take what I said as espousing that.