When you want to hang out with the kind of people who agree with you on topics over which there's pretty substantial and widespread disagreement, that's an echo chamber.

It doesn't even matter what you want, though wantings suggest a causal chain to get there. If for whatever reason you end up with a bunch of people who agree with you on topics over which there's a pretty substantial and widespread disagreement, that's an echo chamber.

All your complex inner drives and thought processes are irrelevant. You get there, through whatever path; you don't get exposed to other views; it's an echo chamber.