> I don't think there's anything about Bsky that makes it "left wing" or an echo chamber

Bsky lacks (1) ads, (2) paying posters rewarded with promoted reach, and (3) a default algorithmic feed (Discover is algorithmic and exists, but the default feed unless unpinned is always Following.) It also has shareable feeds, as well as the default pinned feeds.

Each of these individually makes most users experience of Bluesky a lot more seeing what they choose to see than seeing what the site owner has a financial or other interest in everyone seeing, which in a sense makes it more likely to be a personal echo chamber rather than a single echo chamber or the mythical perfectly unbiased online marketplace of ideas.

OTOH, it also got a lot of users specifically in reaction to negative feelings about the central ideological direction perceived at X, which may make it on average more left-wing by comparison, if very much not uniformly left-wing or having any fundamental trait tending toward remaining even relatively left-wing.

You aren't wrong, but I'd add that it's also just the never-ending grievance-politics of the reactionary right. Spaces that have them but don't amplify their voices enough are censoring conservatives. Spaces where people can moderate what they get who then opt out of it are censoring conservatives. Endless victim posturing about how silenced all these people are who paradoxically also never shut the fuck up.

They love the notion of the marketplace of ideas until said marketplace tells them to kick rocks and then it's crocodile tears.