Well I'm not familiar with the region, that's why.
Welcome to FiC! Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
I mean sure the Caucasus has plenty of muslims but it is the primary stomping grounds of Georgians and Armenians, both nations christian numerous and powerful enough at the time to claim majorities in many areas.
If the choice is between the Safavids and the Russians naturaly both Georgian and Armenian kings and nobles would choose fielty to the Russian Emperor in a heartbeat.