Nice. They completely and totally have control over who accesses their servers. if what you’re saying were true, they wouldn’t be able to stop an hacking attempt initiated from software piggy-backing on their game-client (for example). As a company, they can stop anyone from doing anything on their servers, period. At most, they would have to pay the monthly subscription.
What they CAN’T do is change the software/hardware of a player, aside from what they TOS/EULA allows. For example, they can’t force you to uninstall key-mirroring software, but they can absolutely ban you from accessing thier servers if you do.
But hey, you’re obviously an expert on legal matters, so I’m sure you already know this, counselor.