And it’s not like we don’t have a down vote button.

I've been banned from communities merely for downvoting posts in them. Such behavior is toxic (on the part of the community's mods, not me), but that doesn't stop it from happening.

Maybe Im not saying this right: Im wasnt arguing for the virtues of echo chambers with that, Im saying, with how fedi is designed, there is no means to prevent someone that wants to make an echo chamber from doing so, so suggesting that one should not allow an echo chamber to exist is a fool's errand. In a more general sense, it seems to me that, either you let people decide what kind of content to see, in which case many if not most will naturally create echo chambers simply because they dont want to see views too different from their own, or you have some means to force people to see stuff they dont want to, which requires some difficult-to-escape authority have power over their media feed and as such is incompatible with decentralized federation (and of course risks that authority pushing everyone into their echo chamber). Both of those things lead to serious issues in my view, so its a bit of a "pick your poison" situation when it comes to social media design. Beyond that though, it does have to be acknowledged that there is simply more content, more messages and people wanting to spread their word, out there than any given person has the time or attention or mental capacity to process. That means that some system must exist that determines what fraction of it all you actually see (even if its just as simple as "the things most recently posted on a given platform when you looked at it"). I can see no way to do this that doesnt introduce biases.