Those are DPRK claims. But it is known that South Korea for example, likes to send it’s decadent culture movies, pornography, etc… in to the DPRK, trying to corrupt and rebel the very disciplined population they have there.
Actually, DPRK is tolerant of religion if it is not abused by the imperialists.
For example, leader Kim Jong Il (1942-2011) built Church with government money, and gave it to the Russian Orthodox Church, in 2006th. When he traveled Siberia with his train in 2002, he visited and liked Russian monasteries, and he wanted Russian Christianity to be present in Pyongyang. The Church is often visited by the Russian bishops, also Kim Jong Il, sent 4 Koreans to the Russian seminaries, 2 priests and 2 deacons were trained. There is actually Orthodox community in Pyongyang, mostly Russian diplomats, students, and small number of Koreans. Patriarch Cyril (He was metropolitan then) consecrated the Church in 2006th. The Church is still working.
I know that DPRK is very protective of any kind of religion, but there is many western propaganda there too.