I think you may be a bit confused as to what socialism is. There’s no one type of socialism. Yes, some authoritarian nations claimed to be socialist (as with the old USSR), but one should not mistake the claim for reality. After all, should we think that the People’s Democratic Republic of Korea is a democracy or a republic? If you were to ask the government of North Korea, they’d eagerly tell you that they are a democratic republic…so are we to assume that all democratic republics are like North Korea?
So it goes with socialism. The claim does not compare to the reality.
A better way to look at socialism is to examine what nations on Earth are the most successful when it comes to a combination of prosperity, personal rights and freedoms, and security…and the most successful nations are the first-world democracies, all of which are socialized to varying extents, including America. The socialized first-world democracies have been the most successful on the planet for the past several generations, so it would be disingenuous to infer that their success is in any way temporary. In other words, to argue that socialism is a sure path to Venezuela-style autocracy and economic doom is to argue against sustained success.
On the other hand, libertarianism, which is in some ways the polar opposite of socialism, has not been shown to be successful. When one travels the third-world democracies, one will see quite a few libertarian ideals at work e.g. no effective minimum wage, low effective taxes, and weak regulatory systems. As a direct result, it becomes difficult to build a nation’s infrastructure, from education to transportation to law enforcement and everything in between.
The status of first-world democracies proves that democratic socialism works. The status of third-world democracies proves that libertarianism doesn’t.