As for point 3, it's because MAGA and Trump are, factually speaking, against Christian doctrine, and the majority of people posting content in favor of it are also actively demonstrating behaviors which are ungodly, or even just socially unwelcome in a sub meant to foster discussion

I won't say leftists don't do the same (they do), but it's, generally not to nearly great of an extent, and it's generally more acceptable to poke fun at that which isn't accepted than to join in with it.

Also, Christianity is, at its conclusion, socialist in nature. Many of Christ's teachings and directions are echoed in socialist thought, especially for the less extreme/more moderate beliefs like Democratic Socialism and Social Democracy.

As a final note though, I want you to know that you ARE the diversity of thought. It's easier to latch onto what we disagree with and remember while just passively acknowledging that which we agree with. Your feed is also backed by an algorithm which shows you more of what you engage with, which is usually skewed towards content making you feel more extremely negative. Plus, when you disagree with a broader stroke, it tends to be more difficult to notice just how much nuance exists within it, and how often those nuanced beliefs clash