From what I have seen, it’s bottom-barrel diffusion/LLM generated engagement farming. Thirst posts, political ragebait, AI Jesus, trippy nonsense; basically anything to farm likes, which users apparently like in aggregate.
It’s notably more obvious than most social media. It’s even more obvious than Instagram, with its flood of bot influencers linking to autogenerated OnlyFans pages/chats.
On top of this, it’s basically the only place Meta can push Muse, as there is little interest in it elsewhere.