It sounds like you already know: that’s simply how echo chambers work. Ultimately the admin (team) does have the literal power and authority to decide what goes into their machine, obviously, and then to a lesser degree the moderators, but beyond that, at the conceptual level those in charge can either serve at the will of the people or become enforcers. Those who choose to comply underneath such a system are allowed to remain, whereas those who prefer to think for themselves leave. It is thus an evolutionary filtration/selection system, ensuring that the system itself will continue forwards along those lines, likely indefinitely.

They have drunk the kool-aide on the whole Might Makes Right ideology. Except only choosing to use that whenever it suits them (e.g. they kick out those who they do not like), yet cry unfair when they believe that same exact mode of thinking is leveraged against them. All the while ignoring the consideration of any other possibilities - such as that it is not the “righteousness” of their ideology that turns people away, but the vehemence with which they push it, even when it violates the rules of other communities where they are speaking. It is toddler logic, crying “unfair” even when the aspect in question is the epitome of fairness. Most of us move beyond that stage quickly in our lives, but for some reason that internet space chooses to revel in it.

And making everything a lot more confusing, some communities there have fine discussions within them. But overall it is an instance with problematic users, and more germane, problematic admins who protect the bullies rather than curtail them in order to fit in more with the rest of the Threadiverse. If you want some more of the intricate details, although as with anything historical some things have changed in the meantime, I wrote this post https://discuss.online/post/13916278, which contains lots of links to as close to primary sources as I could find about each matter.