Huh?
Yes, Saudi Arabia has holy cites, but that doesn't give them the right to destroy churches. If you really destroy their churches, then don't get surprised when non-Muslim countries start destroying mosques.
If they want to do Shirk, let them do it, it's Allah who will judge them not us. Prophet Muhammad (PBUH) didn't kill the kuffar when he entered Mecca, but instead, he forgave them them.
Remember, " لا إكراه في الدين ".
Protection of minorities is guaranteed in Islam.