Anyway the risk of creating an echo chamber on Mastodon exists: if you are on an Instance run by a community that refuses any interaction with everyone that doesn't share your views you can easily isolate yourself.
But that also happens in real life if you refuse to hear anything but yourself!
That's up to the maturity of a community to be more or less open to the others!
You cannot force somebody to hear you: it never works.
At the opposite on comnercial social media your echo-chamber is created not by you but by algorythms that decide what you must see and what not, who you may follow and what is the topic you should care today.
Which of the two approaches is more human?