Communism hated religion because of the control it exerts on the masses it wants to be the only pillar in society. hard to make someone do something in fear when they live with the hope in next life they are rewarded for deeds done today when you live just for today. Yet every communist state has had religion no matter how persecuted.

Agree, religion was not forbidden, but you could not expect to “grow” or be successful in your field if you showed that you are religious. In most of the cases it could be understand like your imperfection (fault).

Of course people still were religious and practice religion.