Here is a declassified internal CIA memo from 1956 that literally says Stalin did not have absolute power and people who think he did don't understand the Soviet system

The idea that socialist heads of state are kings is ludicrous and ahistorical, a product of western movies and TV during and after the red scares

I’m simply saying that giving one man absolute power whether it be political

This is standard anti-communist propaganda that unfortunately happens to work on gullible people. It's related to medieval era witch hunting, where you:

1. Create a legend of a supremely evil / nefarious thing, you want to demonize. IE the devil, leaders of revolutionary movements like Robespierre, Stalin, Castro, Mao, Kim Il-Sung, etc.
2. Claim that all people are under the dominion of this sole power, which removes their humanity, and ability to reason or think like you do.
3. Carry out societal-wide demonization and extermination campaigns, to terrorize any potential sympathizers.

Its a really effective tactic that lets you blame a single entity, encourages conformity and intentional ignorance, lets westerners ignore the functioning democracies of socialist states, and the mass movements that supported these various leaders.

"Market" Socialism is not necessary. Socialism pursues a dictatorship of the proletariat, not the total eradication of the bourgeoise. This means that socialism has to have some form of private ownership and thus some form of market.