First, I know what most of you are going to say. I myself was an internet atheist 20 years ago, quoting Dawkins and Sagan at magic-sky-daddy believers. But this isn't about convincing anyone to believe.
This is about pragmatics. And, pragmatically, the single biggest enemy right now is the conservative Christian right. Anything to fracture that coalition benefits the left.
Luckily, their gospels are pretty left-wing. So, I offer for your consideration, the Christian angle.
I encourage those of you who went to Sunday school to brush up on your Scripture. Matthew is a treasure trove. When you're talking to someone on the right, start hitting them with chapter and verse.
If nothing else, this is initially shocking. They're supposed to be the Christians, and you're some filthy commie reminding them that Jesus called the wealthy priests hypocrites, and told us to feed the hungry and aid the sick.
They have defense mechanisms against your crybaby commie talk. They don't have defense mechanisms against their own scripture. At worst, you shake them loose from their script and confuse them, giving you openings for gentle deprogramming.
At best, they might reflect on their leadership and how closely they follow Jesus' commands. Anyone who really believes in him and really reads the gospels is going to wind up a leftist, whether they call it that or not.
Just food for thought. Read up on what Jesus said, use that against the people who claim to follow him. You don't have to believe yourself to recognize a powerful rhetorical tool.
Unfortunately, the chuds in my parts are usually not religious (the original Nazis weren't very christian, at times even anti-church, and that is pretty directly the tradition that many of the local chuds stand in). Or they're a slightly different flavor of chud, i.e. far right / ultraconservative muslims - those don't have a lot of impact in the grand scheme of things, but they might still be the ones who beat you up if you e.g. look like a man in a skirt. Any tips on how to convince or at least confuse far right muslims?
On the bright side, the churches in my parts seem to actually be pretty leftwing compared to US churches. Not quite communist, but they're constantly in conflict with conservative and far right parties (and the pope, if catholic) over stuff like immigration policies and on how to treat LGBT+. Still doesn't make me a believer, but it's nice to know that someone has some amount of conscience around here.
Jesus is in the Quran more than Muhammad actually, faithful Muslims still treat Jesus as a prophet, just not God incarnate. I'm not sure similar tactics would work with them unless you look the part.
I wouldn't shy away from frequenting an actual good church. Even if you don't "believe", it's a powerful way to build community, which is increasingly necessary these days. Might be worth at least sitting in the back for a couple Sundays.
Unfortunately, my local denomination's style of sermon makes my skin crawl. Not really the content, just the specific delivery.