The proletariat is the group of people who are propertyless and thus have "nothing to lose but their chains." The proletariat is the least conservative element of society. The bourgeoisie is the class of people who appropriate the labor of wage workers through their control of the means of production.
Dictatorship is organized force. According to Marxism, all governments are dictatorships. When classes are abolished, it may be possible to have no dictatorships because governments will be abolished and replaced by voluntary cooperation. We communists admit to having dictatorship governments until we achieve our goal of classlessness. It's a matter of accountability.
Dictatorship of the proletariat is the government of socialism. Dictatorship of the bourgeoisie is the government of capitalism.
Concretely and with reference to North Amerikan ideas, dictatorship of the proletariat is government implementation of "survival rights" above "property rights."
The realization that the right to life itself can not be negotiable favors the proletariat. Along with that realization comes the notion that a non-negotiable "right" implies the use of force to protect it from those who profit abusing those so-called rights. The use of force or law backed by force (government) to feed, clothe, shelter and otherwise protect survival rights is dictatorship of the proletariat.
The dictatorship of the proletariat is the most central question of socialism. We do not water it down or evade it. The whole Cultural Revolution in China (1966-1976) was about how to maintain and strengthen the dictatorship of the proletariat so that it would not be corrupted. We communists are not Liberal. We do not tolerate those who put profit or such goals above survival rights. We favor repression or control of such people until the causes of their twisted thought have been removed and bourgeois thought has become completely impossible to the whole people. That will only happen under advanced stages of communism.
Because there is no exploited white working class in North Amerika, MIM favors the joint dictatorship of the proletariat of the oppressed nations (JDPON). This amounts to putting u.$. imperialism into receivership by something like a proletarian United Nations. The whole dictatorship of the proletariat idea or its current form required as JDPON is a strategy for advance from capitalism toward communism, in which dictatorship is only a stage existing until certain tasks eliminating classes are done.