Of course united were going to try and hijack this, they have to, it does irreparable damage to their brand if this comes off. They can not stand by and not be seen to be trying.
The thing is, Ronaldo has known he could go back to united in an instant whenever he wants, United would bend over backwards to accommodate him. He clearly doesn't want to go back there, otherwise he wouldn't have made contact with us. he wants to be at the best club possible to win whilst he can and signing for United puts him in a weaker position to do that than he's in at juve now.