If you start posting promoted content on a Mastodon server, many instances will immediately defederate with you and/or add you to Fediblock. It's fine if that's something you want to do, and there's nothing in the protocol that stops you from doing so, but everyone else will stop "being your friend" so-to-speak. That's probably why most people wanted to leave.
Oh, then I guess I don't really see what the problem is. It's a platform that lets you move your account freely, of course people are going to leave if you start smearing shit on the walls.
As you know, you see ads everywhere outside, and on many websites, including this one. If this genuinely feels like "shit smeared on a wall" to you, you really need to seek help.
