When an agreement has clauses like reasonably necessary for the management or protection of the licensee’s network, then you have nothing to complain. Well at least you can't reasonably complain about them violating the agreement, because a clause like that basically lets them do what they want.
Even if they had to prove that not allowing the Nexus 7 is needed for the protection of the network, it would be trivial for them to come up with some reason and all attempts to prove them wrong will end up with "your $REASON is no valid argument. I can't tell you why though because that's a trade secret".
Whenever you read an exception like this, be assured that the whole agreement is worthless because anything can be tailored to fit that exception.
Even if they had to prove that not allowing the Nexus 7 is needed for the protection of the network, it would be trivial for them to come up with some reason and all attempts to prove them wrong will end up with "your $REASON is no valid argument. I can't tell you why though because that's a trade secret".
Whenever you read an exception like this, be assured that the whole agreement is worthless because anything can be tailored to fit that exception.