Besides, they have the legal right to limit access to their multiplayer servers by any criteria they want.
I think you are just covering for them. If they don't want everyone on their servers, stop forcing everyone to use their servers. It's that simple. You don't get to claim its too expensive and not fair to offer these services when you force your games to use them when it is not necessary. They can offload all they want by offering dedicated servers, third party matchmaking services or directip. Otherwise, it's just lame excuses.