Wow, I really don't know how to start to respond to this! Maybe I'm too "cranially challenged"? ;) You've mentioned quite a few cliched tropes, which I'm sure

Wow, I really don't know how to start to respond to this! Maybe I'm too "cranially challenged"? ;) You've mentioned quite a few cliched tropes, which I'm sure you can already find many suitable echo chambers for. I find it interesting that you consider that such groups do not already exist, considering the current rise in right-wing, pro-extreme capitalism and anti-intellectual movements across the globe. I worry that you think they are too much talk and not enough action, as many a wrong action has started with that thinking. I would suggest you do the opposite of what you intend: have more in-depth and open discussions with people who do not share the same core beliefs as you. Not arguments, shouting matches or meaningless online factoid swaps, but open discussions where you invite in and really ponder different opinions. Accept that pretty much everything is more complicated than it first appears and all an echo chamber will do is reduce thinking and reduce the essential nuance of viewpoints.