The echo chamber argument itself is a politicized argument that I think fundamentally misunderstands why communities converging on common values can be beneficial rather than simply echoing.

If people are interested in astronomy, or tech security, or FOSS, or politics, weeding the garden leads to more dynamic, diverse and nuanced communication, not less, and the diagnosis of such things as "echo chambers" is a shallow misdiagnosis. Opening up your garden to weeds kills everything and leads to takeover of the one dominant kind of weed that already dominates everywhere else, which is more echoey.