That’s all allowed within the world of open source. Don’t think there’s any ’splaining required.

Dependent on licence though. It's only relatively recently that the blockchain code license allowed for a new genesis block to be created, i.e. a new blockchain, on any derivative of the Steem source code. You might remember @dan wrote a post drawing attention to this the day before he left which he subsequently "deleted" by editing to update to blank document.

Open source ≠ free for all uses.

If they are forking I agree with you, let them do it (not that anyone can stop them). I'd even go as far as to say we should encourage this. Competition can only be good for us.