You're making a dichotomy that doesn't exist. Democracy and Communism are not on opposite ends of a spectrum. Socialism is also not contradictory to democracy. Look at the proper name of Sri Lanka. It's the Democratic Socialist Republic of Sri Lanka.
Like I said before, the foundation of the USSR was supposedly to create a Proletarian society. No haves and have-nots, an equal society where the people benefit equally and actions are taken for the good of the group.
The theory isn't the problem. It's the people interpreting and implementing the theory that are the problem.
The USSR said it was made up of Republics, but did they actually have people electing representatives?...
So was it really a Republic?
Good...often confused point. Thanks for bringing that up. To add a bit... Democratic rule is best paired up against totalitarianism, either through oligarchic(USSR) or despotic(the vast majority of governments from the beginning of time) rule.
Communism should be paired with Capitalism and Socialism falls somewhere in between. It is essentially a continuum from one to the other which describes to what degree you allow your government to control your economic sphere.
Most governments in the modern world elect to institute some level of socialism. To what degree you are socialist varies from state to state (referring to country states not states of the U.S.) as does the degree you admit to socialism.
Even the U.S. is a highly socialized state. We were probably closest to achieving a capitalist state in the period between the Civil War and WW1...then Upton Sinclair came along and we have seen increasing regulations governing business practices ever since. Many Americans claim they want to be capitalists but very few want to work in a sweat shops.
If anyone is interested in the rise of philosophical capitalism I recommend you read Max Weber's "Protestant Ethic and The Theory of Capitalism." You could also read Karl Marx's "Das Kapital" which is his less dogmatic, more analytical critique of capitalism and communism. Don't bother with Marx's "Communist Manifesto" as it is more of his ideological viewpoints than a rational critique.
In short, you can be a totalitarian despot and a capitalist and you can be a republican and a communist.