It's a good and necessary thing to become "radicalized" in order to prevent genocide and break out from the pacifying programming of the state. the state puts pressure on centralized social media companies to enact clever methods of censorship to pacify the masses for them. such companies might even just willingly self-censor in anticipation out of obedience or just plain uncritical acceptance of state department propaganda.

So the state and the ruling class produced a radicalization of the masses themselves where the status quo is to pretend that genocide is normal - a "zone of interest" type of effect is supposed to be part of what's "normal". While I agree with you that decentralization is not a silver bullet, because it can create pockets of echo chambers, it's still a good tool for communities to be independent from certain influences like from the state or corporate culture.