He doesn't deny that his point of view forms an echo chamber.

"flat earth creationists would describe their colleagues the same way."

Actually they mostly don't. Lots of infighting over the real true answer .. (infinite flat earth, finite but with impassable ice walls, ..)

An echo chamber is a product of your own creation. If you're willing to upvote people who disagree with your and actively seek out opposite takes to be genuinely curious about, then you're probably not in an echo chamber.

The tools for controlling your feed are reducing on social media like Instagram, TikTok, Youtube, etc., but simply saying that you follow and respect the opinions of a select group doesn't necessarily mean you're forming an echo chamber.

This is different from something like flat earth/other conspiracy theories where when confronted with opposite evidence, they aren't likely to engage with it in good faith.