Tim Sweeney has made some statements about this, to try and walk a line where, while the situation is equally true about game consoles, they shouldn't count/shouldn't be forced to be open because their platforms are less innately profitable. That is, consoles are sold at a loss and have a lot of R&D costs, and so they have more rights to maintain an exclusionary platform than Apple.
I can see the pragmatic sense in that argument, but I'm pessimistic and see it more as Tim trying to avoid destroying a relationship with strategically critical partners while achieving new strategic goals on mobile. Trying to have his cake and eat it too.
Let's assume your pessimistic case is exactly right, so what? He's allowed to sue one person who is breaking the law while not suing another one. He's allowed to eat the console slice of cake and complain to the courts that the apple slice of cake had the wrong color icing even if they both have the wrong color icing.
He's also allowed to believe that there is a stronger case against Apple and sue them first, and then sue the other people later if he wins the first suit convincingly, which is what I personally suspect is going to happen.
I can see the pragmatic sense in that argument, but I'm pessimistic and see it more as Tim trying to avoid destroying a relationship with strategically critical partners while achieving new strategic goals on mobile. Trying to have his cake and eat it too.