Twitter has plenty of leftists. They are very, very, very easy to find, as is every other shape and size of political, ideological, or spiritual thought; far easier than, say, a non-leftist viewpoint on the worldnews or politics subreddits, which because of their default status are much more inescapable than any one Twitter account.
There are very, very few non-left people on Bluesky. "JD Vance Becomes Most Blocked Person on BlueSky Days After Joining App" <https://www.newsweek.com/jd-vance-bluesky-blocked-social-med...>
Even Bluesky's top users say so.
"Bluesky is backfiring. Mark Cuban says the 'lack of diversity of thought' is actually pushing users back to X" <https://fortune.com/2025/06/12/bluesky-backfiring-mark-cuban...>
"Bluesky is not the good place" <https://www.ms.now/opinion/bluesky-elon-musk-twitter-replace...>
But it could be worse. Bluesky has block list dissemination (à la how, if you make one comment in a "wrong" subreddit, a whole bunch of others will automatically ban you despite never having even heard of them), but I don't think even it ever gets so bad as individual Mastodon instances' ability to self-destruct in spectacularly amusing fashion. mastodon.lol example over Hogwarts Legacy. <https://news.ycombinator.com/item?id=34748195> As rvz said in the link,
>This is just one of many Mastodon instances which are undergoing an extinction event which involves: turning against themselves and destroying each other. This time, it is over a children's video game.
That said, I suppose that such self-immolation might be a good thing; sort of an immune system-like response. There are many, many mentally ill that steep far too long in Bluesky (and 80% of Reddit)'s ever-boiling toxic soup.