No, it hasn’t.. Steemit.com is owned by a private company and has to follow rules sometimes. The darkoverloard was doing things that would have put them in legal trouble and they made the decision to remove it from their interface. Others don’t have to as they are not in the same legal jurisdiction and of course nothing is removed from the chain.
They have also removed spam accounts from the interface that can still be viewed elsewhere.
People just like to use this one example to somehow back up their censorship claims.. when all they mean are downvotes, as they have not been removed from the interface, clearly. 🙂