I wonder what the breakdown of discussions started from users vs. bots is. While I can see your point especially from a spam pov, one purpose of this kind of bot is to pull from other sources and get a conversation going. If no one is interested, then it just falls to the bottom. I often see posts complaining that Lemmy/fediverse isn't as active as Reddit was/is, and yet without some of this automation it would be far deader as people don't tend to start posts as much as reply to existing one. If a particular bot/community is flooding your feed too much, that can be easily be blocked, or let the mods/admin know that it needs some adjustment.