Better than no one having the ability to follow that person because a centrally controlled social media banned them.

You can choose. But you don't have to.

The official Mastodon app has a box where you can pick one out of several hard-coded instances. It defaults to mastodon.social. You can pick a different instance if you want to. But you can also ignore it, scroll past it and let yourself be conveniently railroaded to mastodon.social without even knowing what an instance is.

Yes the choose was there but it automatically was filled with a default instance.