Your initial comment that Sunday Schools were closed down in Russia was just a little narrow imo. I’m sure that those denominations which have the required permission to teach have no problems operating Sunday Schools.
If Russia doesn’t want certain protestant denominations whose origins are from foreign countries, there’s little you or anyone else can do about it.
The idea of certain denominations using religion to undermine a government shouldn’t come as a total surprise to you, should it? Don’t you wish the same applied to islam, which isn’t a religion but a cult bent on domination?
Freedom of religion is somewhat of a two-edged sword, as we are all discovering. Islam gets all the freedom, and we get nothing. Using religion as subversion is not going to be tolerated in Russia, and that might be a good thing in the long run.
Russia’s continued low-level harassment of the Roman Catholic Church doesn’t fit within your theory. How can that be excused under the rubric of state security?