They have ritualistic acts: moving missiles back and forth in the hope that it will bring material wealth. Below I take the text from Wikipedia with my comments in brackets:
Cargo cults are marked by a number of common characteristics, including a ‘myth-dream’ [Juche] that is a synthesis of indigenous and foreign elements [Marxism]; the expectation of help from the ancestors [Kim Il Sung, Kim Jong Il]; charismatic leaders; and lastly, belief in the appearance of an abundance of goods.[Communistic paradise]
Since the modern manufacturing process is unknown to them, members, leaders, and prophets of the cults maintain that the manufactured goods of the non-native culture have been created by spiritual means, [Capitalism] such as through their deities [Adam Smith, Milton Friedman etc.] and ancestors. These goods are intended for the local indigenous people, but the foreigners [Western countries] have unfairly gained control of these objects through malice or mistake. Thus, a characteristic feature of cargo cults is the belief that spiritual agents will, at some future time, give much valuable cargo and desirable manufactured products to the cult members.
This is why NK regime wages war on markets. It is direct attack on their cult. People do not have to believe cargo cult if they can get what they want from the market. At one point(around 2005~6,) markets in NK are taking roots. There were even underground commerical package delivery service all over the country. Somebody outside send money or a letter. It enters into a network of couriers, from Sino-NK border all the way into the heartland of NK, after changing hands several times. They can get something out of NK, too. Letters, secret internal documents, and even people. Of course, the markup is high, but the system was reliable. Kim Jong-il's all-out war on market naturally destroy the network.