If an app is open source why does it matter who controls it?
If an app is in Git, then you have a fully copy locally, so why does it matter who hosts it?
Git is and was absolutely decentralised by nature. Everyone can have their competely independent copy of the copy and can send diffs/patches as emails, text files, whatever.
Thereโs no concept of a central server in Git. GitHub is not the center of git. There is no Center.
Then because most young devs couldnโt properly understand git and weโre too lazy to learn, you all adopted a pattern called โrebasingโ which has now become gits default. It plays into the idea that GitHub is the single source of truth when it need not be.
Anyway thereโs an off topic git rant for you.