I don't understand this.
If the same "Pussy Riot" girls were in the U.S. and disrupted an ongoing a church service by storming the altar and singing offensive lyrics (probably out of tune) they would also be in jail. This kind of disorderly behavior fits several criminal misdemeanors, and they could also be sued. In Russia they are getting a bit more jail time than they might have in America, but I don't see a great injustice being done.