Be fair, it isn't like many self-described Communist/Marxist countries have a great record as far as respect of human rights go or the enabling of free and open elections- at least on a national level.
As far as "free" elections go, they're a bourgeois institution with bourgeois expectations built around it. They're not an objective descriptor of "the will of the people," and even if they were, there is no inherent value in that expression. So they get to have a say in who their leader is? The class in power cannot help but dictate the structure of society. Elect a bourgeois politician, they will pursue bourgeois interests. Even a socialist elected in a bourgeois system will still have to fight very hard from now pursuing the ruling class' interest. Look at Sanders, caucusing with the Democrats! Even if he does get to sneak some working-class rhetoric in there, he's obliged to pay homage to the Democrats' favorite "middle class" too.
So why is socialism any different? Well let me ask you what the purpose of bourgeois society is? What is its goal, where is it going? It's goal is its own perpetuity, its purpose is to reproduce capital (and the wealth) for the benefit of the bourgeois class. It is going nowhere except where the pursuit of profit takes it. Thus, as long as the bourgeois class controls the state, it controls society (because the state is the mediator between class antagonisms - it can always decide in favor of the bourgeoisie), and that is all that it needs.
But socialism is different. Socialism works toward something: communism, and the abolition of class antagonisms, privileges, and all forms of discrimination, bigotry, ostracization. It is the dramatic restructuring of society into something permanently capable of maintaining maximum freedom for everyone, and keeping everyone free from the domination of others.
Getting there is the challenge. Critics point to extant socialist states and say "oh look how disrespectful they are of human rights and liberal freedoms" and "look how underdeveloped they are," and so on. Well as I said, liberal freedoms are the enshrinement of liberal (bourgeois) society. There, they exist for their own sake, because they enable the perpetuation of private capital. But we understand them, like all things, to be
means to an end: they don't exist for their own sake, they exist for our sake. If they prove to be more harm than good (like allowing free elections which will bring back capitalism: would you as an ex-slave allow any say in the re-institution of slavery???), then they are put on hold. Bourgeois society does this as well, don't be fooled. But it does it in protection of its dominant class: the small caste of highly-rich bankers and industrialists who rule the rest of us for their own benefit. Socialism does it for the protection of its dominant class: the great mass of workers (and sometimes peasants and intellectuals - a great many unique alliances in different countries have developed).
When socialism is not so hard-pressed, besieged on all sides by imperialists, always threatened with extinction and that return to subjugation, and the institutions which redistribute wealth can function more freely, then power in society will be able to flow downward. It is not something to be weighed "in equal measure" with capitalist societies; they are not equal, one is the acme of one system with all the strength which that position enjoys, one is the beginnings of another, fighting the uphill battle in the dark.
At heart, all communists are anarchists, don't forget that when judging the "motives" of communists. Of all the virtues, the communist possesses only one: that he struggles for communism. We will do what we have to to survive a return to capitalist wage-slavery. Any escaped slave would. The difference between us and Spartacus is that we don't just want to go home, we want to get rid of slavery everywhere, forever. And that requires sacrifices.