It's just their go-to thing to say, isn't it? “This sub is just an echo chamber.” “reddit is such a hive mind.”
I ask you, what is the difference between an echo chamber and a large group of people who genuinely, honestly disagree with you? What are we supposed to do, designate a group of people to agree with some hateful bullshit so the conservatives don't feel left out?
If you are someone who just really enjoys eating worms, and you go into some sub and talk about how you love eating worms, and almost everyone is like, oh wow yuk not my thing at all gross — is that sub an echo chamber? Have all those people just been brainwashed by diabolical anti-worm-eating propaganda perpetuated by the liberal media?
No. Worm eating is just yucky. [anyone who wants to talk about sustainable protein sources of the future etc., calm down. this is just a metaphor.]
In my view, if you have a large group of people that you can convince of something you just made up, with no evidence whatsoever, that is patently false; and not only that but convince them everyone else in the entire world is lying — well that sounds like a hivemind to me. Hiveminds, like conservatives, are opposed to critical thinking.