Old twitter (and new twitter) was/is private property, and the owners can do what they want with it - be as unfair as they want. Like a biased newspaper owned by a billionaire.

That's the root problem. If you want the websites of (some?) private companies treated as common carriers that's a reasonable position to take, but Twitter was/is working as designed.

(If I was king for a day I'd force all social media to only present you with posts from people you'd actively followed, and to present those posts most-recent-first. I think that single UX change to timelines would clear up many problems we currently have).