I'd heard about Lemmy a good while back, but there wasn't much interest in it until the Reddit API kerfuffle.
I really like the concept of federated social networks and breaking free of the big tech rage-baiting algorithms. Just give me a list of topics I can follow and let me sort and filter them how I want. Don't suggest or recommend things to me, especially if they're designed to make me angry just for sake of engagement.
Lemmy seems like it has a lot of potential in that regard, and I'm hopeful it's able to build a respectful user base. I'm primarily here to feel out the landscape and be the change I hope to see in the world.
I joined Lemmy for the same reason. I'm not ok with the way social media companies use recommendation algorithms to increase engagement and make their users feel shitty. Since Reddit is going public soon, I'm sure they're going to start coming up with new, manipulative ways to increase engagement, which means it's time to jump ship.