Followers only posts and requiring followers to be approved by the account they are following is common on the Fediverse.

This is what vulnerable folks I follow do to protect themselves, along with their instance admins often blackholing (IP tables dropping & blocking in their instance config) shit holes like https://freespeechextremist.com

I say this as a person banned by https://freespeechextremist.com , apparently my toots on that Pleroma instance should have been racist, and most other speech is unacceptable there.