Twitter was very diverse. You could see just what you wanted to see. My twitter was very liberal and tech oriented. But now everyone left.

Eh, some of them. You weren't generally banned for "merely" being right wing. But pre-Elon you generally had to toe the line a lot more to avoid being suspended or banned if you were overtly right wing than if you were liberal or left and now it's the other way around.

Just like how the blue check started as an "I am a public figure and this account is definitely who I appear to be" mark and that's it, then it became a mark of who you knew/could bribe at Twitter to move the process along and could be revoked for saying the wrong things on Twitter (for example everyone's least favorite gay right wing provocateur Milo Yianwhatever had his blue check stripped for saying something too offensive well before he was banned), then post-Elon it became just a subscription service.

There was also a tendency to quietly artificially reduce visibility for a lot of right wing voices or hashtags. For example, female MRA and member of Honey Badger Radio Hannah Wallen literally got a bunch of her fans to do some pretty elaborate testing of her account at one point after her engagement numbers suddenly and mysteriously dropped and it turned out many of her posts were invisible except to people that followed her that she also followed, even to people specifically looking at her feed.

Certain right wing hashtags would have numbers that should definitely have them trending but mysteriously weren't (or would be for just a few minutes and then suddenly vanish despite gaining popularity in the meantime), certain liberal/left hashtags would be trending despite seemingly not having the numbers for it to be organic, that sort of thing. Because Twitter moderation was curating what was and was not "trending", literally blacklisting certain topics and bumping up others because of the visibility that being trending would afford.

It was all really, overtly obvious if you watched for it, like how certain accounts would be shadowbanned on Reddit for reasons that were both obvious and not spam-related despite shadowbanning supposedly only being employed as an anti-spam tool, or how certain subs would be allowed to openly ignore certain sitewide rules.

twitter would be bankrupt if they didn't exist