... That's not an echo chamber though. That's propaganda and vote manipulation mostly by literal state actors and brainwashed rubes.

An echo chamber is when people literally self segregate enough to the point that they no longer consume almost any media that doesn't fit their belief. Its exacerbated by large corporations who profit from ad revenue driven through user engagement.

Lemmy is not an echo chamber no more than the literal radio.

Reddit is not an echo chamber.

You can make these an echo chamber through varying degrees of ease. But places like Facebook, YouTube, and Twitter have been proven to drive you into one by exploiting ragebait for clicks.

You can say they're both fruit, sure. But one is like eating cantaloupe and the other like eating bananas laced with speed.