BTW, the info about Samuel Dickstein at that link was quite telling. Lots of Soviet moles in the HUAC, and they succeeded in bringing it down.
In order to ensure to citizens freedom of conscience, the church in the USSR is separated from the state, and the school from the church. Freedom of religious worship and freedom of antireligious propaganda is recognized for all citizens.* Take note that incitement of hatred and/or hostility on atheistic grounds was not prohibited.
1936 Stalin Constitution, Article 124
Citizens of the USSR are guaranteed freedom of conscience, that is, the right to profess or not to profess any religion, and to conduct religious worship or atheistic propaganda. Incitement of hostility or hatred on religious grounds is prohibited.* In the USSR, the church is separated from the state, and the school from the church.
1977 Brezhnev Constitution, Article 52