There are dozens of us!

I would say my experience on midwest.social aligns with Lemmy's population as a whole - generally left of (US) center, with a few further left folks. Most of the content is either midwest-specific news or LOTR memes, probably makes sense that the only content that gets widely upvoted by Lemmy at large is the left-leaning memes.

I haven't seen anything nearly as extreme as the posts/comments from hexbear/grad/ml, but I wouldn't be surprised if users from those instances have accounts on multiple instances to push propaganda.