I think Russia's right to be strong against open Satanism and open vulgar acts but I think they're wrong to suppress free speech with lengthy prison sentences, especially if the women have children to care for. I think fines would be more appropriate.
I see this as open attack on Orthodox Church and its believers. They already performed anti-Putin concerts before and were not arrested. However, in any society they are limits to what you can do. There must be some rule of law. You see soccer hooligans get prison sentence for riots so why feel sorry for prison time they got for hooliganism and discrimination against religious Christians?
If they wanted to protest they could register their meeting but you will not call for another genocide against Orthodox Russians and that is where they crossed the red line.
Their lives are destroyed because they will be made example for other crazy satanists who plan such attacks. It is too bad they took such route but we all make decision in our lives.