It's like you think we're all evil propagandists or something. We're people like any other. We want the world to change for the better, not just for us, but for everyone on Earth.
Most people here will tell you that socialism is worker control over the means of production. This really boils down to nothing more than wanting "more democracy"; people having control over their lives. This definition is is largely derived from the pertinent socialist literature.
People who haven't read socialist literature can only work with what they know, and what they know typically comes from mainstream media sources that they've been exposed to their whole lives. This mainstream view of socialism is, if we're to be generous, a half-truth at best.
It's a little ironic that you would call socialist literature the "propaganda source", because this mainstream view is rather obviously a propaganda source too. It has lead people to feel very negatively about something they actually know nothing about.
As for the well-read anti-socialists, I ask you to consider this perspective. History has near-infinite nuance. It's practically impossible for the average person to know every little detail about the conditions of the past, the events that occurred, the people involved in those events, and so on. Many people who have been affected by propaganda themselves produce more propaganda because, even though they believe they are being objective and truthful, their emotions, their biases, inevitably affect their works. "Primary" propaganda that is produced with intent to deceive is actually relatively rare, but the biases it creates in the general population leads the propaganda to reproduce itself until it is widely accepted as fact.
To roundly declare, "USA good, USSR bad" says little more, to me at least, than that one has been strongly affected by propaganda. The bad of one has been highlighted and its good suppressed, while the opposite is true of its foe.
The reality is, of course, far more complicated. One has to keep an open mind about history and politics. They are an absolute minefield of propaganda and lies.
So I simply ask you to consider that what you think you know about socialism, communism, capitalism, Cuba, China, the USSR, and whatever else, is not the end of the story. You can call socialist works propaganda if you wish, but to be consistent, then you must also accept that everything you know about the issues is rooted in propaganda too. I personally feel that it's a good rule-of-thumb to be particularly sceptical of whatever the mainstream view is.