A feature of Bluesky is the ability to change your feed algorithm (or code your own - yes I wrote ‘code’). You can easily filter all political (labeled) content. To say that BS is an echo chamber is untrue, though I do not disbelieve that you observed that algorithmic choice when you first tried the app. There are many echo chambers for sure, but the protocol is designed to permit you to exclude or join them. Unlike competitor systems (which I also use, and dislike more and more due to the lack of ability to choose what I see - despite trying).

Right, and what's more the charge of echo chamber has always been intellectually lazy.

You can have a fruitful exchanges of ideas and information and debates on a foundation of similar values in a way that amounts to more than just repeating ideas back and forth. Using the term as a catch-all for a shared desire for conversations to have certain ground rules or certain community values, or subjects that spark your intellectual curiosity, calling those echo chambers is shallow and is not going to inform you about the real cultural dynamics that drive those kinds of communities.

It's just a lazy way to try absence of critical thought by looking for the wrong thing. If people labeling things as echo chambers cared about the things they said they cared about, they would look at entirely different criteria, such as epistemic closure, the quality of relationships, propensity for trolling, and so on.