1) Nazism was always, from the very start, explicitly about doing this. It was not an attempt at "true" socialism that degenerated into this; it was 100% intended to divide people into the Master Race and the Inferior Savages.

2) From my understanding, the only times a country has ever claimed itself to be "fully socialist", or attempting to be so (rather than democratic socialism, like various northern European countries), the countries have actually been authoritarian dictatorships with a few superficial trappings of socialism-for-the-few.

3) The common counterargument I have seen to #2 is "but that's just a No True Scotsman fallacy!" It is not. No True Scotsman applies when there is some potential fuzziness to the definition of the term that the person committing it is exploiting to try to argue that the thing is not what is being claimed. The USSR, for instance, was no more Socialist than the DPRK is Democratic; it was so in name only, in an attempt to claim that it was a genuine step on the road toward Marxist communism, when in fact it was just an authoritarian state. The term "Socialism" does not stretch to cover "any state that declares itself to be Socialist, no matter what its actual policies are."

4) As a global—and especially Western—society, we have more abundance today than we have ever had before. We have vastly more capability to produce food, medicine, housing, and all the other necessities of life, as well as modern conveniences like internet, computers, and smartphones, and even luxuries, than we did during the periods in the 20th century when various countries were attempting to convert to communism or socialism (and being, almost universally, co-opted by dictators). Even if we grant your premise in full, that we have, as a collective, been unable to sustain socialism in the past due to a failure to actually provide for all people does not mean that such conditions are still in effect. It certainly does not mean that they will hold forever.

5) Really kinda suspect that you post this as a snide response to a post very specifically explaining what Nazism was. Though somewhat less surprising looking just a little bit into your comment history.