> Thing is, marxist-communist-socialist countries don't even stay non-dehumanizing-regimes.

There are no Marxist regimes; all “Communist” regimes are (or are derived from) Leninism which introduces vanguardism and other changes to avoid the prerequisite of developing proletarian class consciousness through mature capitalism in Marxism, and feature a (theoretically) transitional initial phase to replace development through private capitalism, which none have ever escaped from to anything that was supposed to be beyond it (though China rewrote the plan to include authoritarian quasi-private capitalism.)

There's a wide array of arguably socialist non-“Communist” regimes, but all of them are democratic/market socialism that explicitly accepts plural democracy and regulated (not “free”) markets as important elements.

> Nazi (national-socialist) Germany was totally socialist.

This is true to about the same extent as “the Democratic People's Republic of Korea is totally a democratic republic” is true.