I have noticed this trend. On the one hand, “Truth has a liberal bias” has always been true. If a community is geared towards truth and evidence, like as not it will lean left. There is copious evidence for this, for any random topic.
On the other hand, it has resulted in a lot of “I downvote complexity” behavior, which is, in my view, problematic. It is very easy to take stances of ideological purity online, and behave as if any recognition of greater complexity is EVIL!!1! I see this again and again. This is a way to make your ideological movement irrelevant and unworkable.
As much as folks decry the rigor of the MAGA right, where fealty to Trump is the only virtue, the Progressive left exhibits the exact same rigor, the exact same intolerance for deviation from its allies. Both Progressives and MAGAts see this as a virtue, but it very much is not: it locks you into a worldview that eliminates important complexity and any ability to see things from alternate perspectives. If you have a belief that your perspective is the only correct one, then the vast majority of the time, you’re wrong.
There is absolutely nothing I said that says I’m a centrist. You’re an example of the problem.