He's completely wrong about how easy it is to move a Mastodon account to another server.
First, your instance admins can completely wipe your account before you even have a chance to move.
Second, you can't move an account, you create a new one on another server which produces a new handle. You can move followers over using some clunky process few users would understand. It can take up to 30 days to process and may require multiple tries. In case any blockage happens between your old and new server, it gets even trickier.
Worse, your content cannot be migrated. It is forever stuck at the old server and at the whims of whoever runs it. Same for the redirect from your old account to your new account.
If the point is to have a robust network where your account, content and followers/followings are safe...Mastodon is the worst.