I was never a fan of the Lemmy developers, who engage in a... concerning amount of genocide and atrocity denial. In fact, I didn't want to swap to Lemmy.world to begin with - I originally picked Kbin despite Lemmy fitting my aesthetic preferences better. But when Kbin went down permanently, I wanted to move all my comms quickly so they didn't die, and Mbin's main instance at the time was... not federating well.
So when Piefed started to become stable, I saw an opportunity to move away from the Lemmy software, whose devs were constantly asking for money even on non-ML instances (as is normal and is necessary for software development - but again, that's exactly why I wasn't comfortable with Lemmy. You're either a free-rider or helping support the ideals of the ideologically repugnant). Rimu seemed reasonable in my brief chats with him at the time - and I still don't think he's unreasonable, per se, just with very... core disagreements about what direction Piefed should be going (ie the notion that 'power users' are undesirable and should be limited) and what that will lead to, especially the aforementioned enshittification of my own, personal experience.