I mean, it's a video. It speaks for itself.
Just as the context supplied by a longer video is better than a shorter video, so context can extend beyond a longer video, too.
I don't believe in attacking the messenger, or otherwise refusing to believe the message because of who the messenger is.
Given a lot of comments you've made about the mainstream media over the last couple of months, this plainly is not true.
I think the similarities come in the fact that they're both authoritarian regimes (USSR at least) that sees Unity as something to not be question and to Purge the world of their enemies and bring about a new world order. They are vastly different in political beliefs, I'm not saying Communists are nearly as bad as Nazis, but with those similarities mentioned above it makes sense that you can see similarities in their art.
It certainly has something to do with their authoritarianism. Well, it's more totalitarianism.
They wanted to bend art to achieve the political aims of the state. Much as I like Kandinsky's paintings, they really do look like a load of colourful squiggles that are hard to interpret as meaning anything at all if you don't have an art degree. The Communists wanted straightforward statues making workers feel proud of being workers on obvious ways. The Nazis wanted straightforward statues inspiring the populace to strive for the greater glory of Germany in obvious ways. It occurs to me I'm maybe being a little harsh on the Communists because they were very interested in progress and the future, which comes across (some of their futuristic modernist architecture is fascinating). The Nazis however were relentlessly, tediously conservative.
We get this even today in public art. A lot of public art is not done by great artists, it's done by graphic designers, whose art perhaps is more tailored to producing something commercially pleasing than the individual perspective of a fine artist. See also the current kerfuffle over the
statute of Mary Wollestonecraft, which has left many looking at the artist's vision and saying to themselves "Mm, that's not what I'd have done" at the polite end, and considerably more caustic stuff at the harsh end.