I did a detailed write-up on the Russian Orthodox Reformation and consequent attitudes to Protestantism over here.

tl;dr: Initially the Russians believed the Protestants to be just about to return into the fold of the one true orthodox church and even have reformed it to accommodate them better, but they would soon be frustrated by the lack of any concessions on the part of the protestant leaders themselves and turned instead on heckling the catholics for even tolerating this obvious heresy.

The geopolitical backdrop included a incessant wars over the Baltic sea between Russia, Poland and (since 1527 protestant) Sweden in which, just like in Western Europe, war, peace and mutual aid was more a matter of convenience than ideology.