So they'll remove accounts that just promote these social media and link to them but allow cross posting from ANY social media and allow links to none of those mentioned so you can link to YouTube or hell link to here.

Seems fair, they're a business so why allow someone to use your 'lobby' as a place to go 'our place is better, go here'. They also targeted only social media that is effectively the same as them as YouTube, Twitch, Bitchute aren't mentioned so content creators are fine. This mainly targets those that are going 'I'm leaving Twitter, follow me on my new account'.