Only totalitarian regimes ban or strongly discourage worship.
In dogmatic, non-democratic regimes (the Stalinist/Pol Pot regimes, etc.), the basis of not allowing religion to be openly practiced is that religious dogma is competition for any other dogma, including non-religious dogma like all city folks must be herded into the country, stripped of their eyeglasses, and killed in the fields through starvation, neglect, and murder as the Pol Pot regime did under the guise of agrarian reform.