No one can stop you from finding or starting an instance with your values. Its the same kind of freedom the copy machine or the home word processor gives.
No, it doesn't let you be a prick with someone elses resources. They have no obligation to listen or amplify you.
Perhaps people's expectations of free speech are a little greedy?
You seem to be confused. No one on mastodon can stop you from speaking. They can just choose not to listen. Censorship would be stopping you from speaking. As long as you're not breaking any laws, no one is going to shut you down and prevent you from being on the network (eg, your hosting company shutting you down). All you stand to lose is a generous system administrator doing the work of staying online for you for free.
Is free speech in your mind something someone automatically has obligation to share? Thats forced, not free.
No, it doesn't let you be a prick with someone elses resources. They have no obligation to listen or amplify you.
Perhaps people's expectations of free speech are a little greedy?