I think some users liked Twitter exactly the way it was, so yeah, there was no need to change anything. Other users were literally blacklisted, or blocked from search, or banned. Or they wanted to follow such people and couldn't.

Yes, some of them were actual trolls or spammers, but many were just ideologically misaligned with Twitter the company (and/or their advertisers).

I think the problem to solve is how can we allow people to communicate AND DISCOVER other people's opinions without a particular company/organization making that decision for them.

Websites aren't good enough because they aren't very discoverable and don't have a robust discussion mechanism. I don't even think Mastodon allows this because admins seem pretty opinionated and end up cutting out chunks of the fediverse without the users' consent.

I'm not sure what the solution is but that is a real problem and it does seem necessary to "decentralize" to some extent as every group will always have conflicting opinions with other groups