I think you have a reasonable interpretation, though I disagree that the endpoint is increased radicalization. Certainly it’s far easier to find people that are on your side, but that doesn’t mean that the number of people that believe what you believe goes up naturally. I think everyone is jockeying around in a new space and trying to figure out what “community” means as conversations move online. There definitely is a radicalizinf element in an echo chamber, but there’s also a lot of wonderful communities being built that could not have. When things start to translate into the public sphere is where it is messiest right now.