To say that "dictatorships" include "communism" and "socialism" means you do not understand the definitions of those words. Dictatorship is a form of government. Communism and socialism are economic systems. If they become totalitarian the sharing the was advocated in socialism is soon gone, and it is no longer socialism (e.g. the old Soviet Union and China today!)
But the economic conditions are what form dictatorships. It's all about control over the pocket book.
In fact, that is why socialism and communism have historically been so appealing to dictators such as Hitler. He called his party the socialist party as he micromanaged the economic activity of the populace so that he could siphon the money to two entities, the military and the welfare system.
Hitler's only goal was the conquest of the world, but he feared the internal uprisings that occurred during WW1 due to poor living standards, so he created a massive nanny state that gave the German people a higher standard of living throughout the war that was even better than the US and UK. Shrug, it worked. He bought off the people of Germany as he purchased their souls so that they would overlook mass genocide and never ending war. There were no uprisings like they saw during WW1
Both socialism and communism demand a never ending micromanagement of every aspect of society. Both systems are the most oppressive ever created.