Retronautickz

Depending on what you’re calling an opinion…

No one is stopping anyone from opening their own instances, but the rest have the right to not federate if the content on that place goes against their own instance rules and personal beliefs. This is the good thing about the fediverse, you can choose the kind of people and content you interact with

You cannot stop someone from downloading a software to open their own instance. What you can do is to block bad actors/cut federation with them. Which is what most instances do with both alt-right/nazi and tankie instances.