Start using the block feature. Honestly I did that when I was active over in Reddit and I do it here too and it makes for such a better online experience.
Doing that I've found that I can have these reasonable discussions, even with those few of the more far left .ml folks that don't mind discussing actual ideas and facts.
I think another key is that unless you're wanting to vent, which I get sometimes you just want to do it, avoid going back into threads rehashing the same topic, they're going to be full of the same people that haven't changed and you've said your piece, they're just actively looking for that fight and echo chamber, downvote, block and move on.
That's the scary beauty of the onion nowadays.