It's worth noting that the nazis were happening at the same time as Modern Art, and the transition from Representative to Abstract art.
Western art had been, from the Renaissance up to the middle of the 19th century, underpinned by the logic of perspective and an attempt to reproduce an illusion of visible reality. By the end of the 19th century, many artists felt a need to create a new kind of art which would encompass the fundamental changes taking place in technology, science and philosophy. (from Wikipedia)
This is a reaction to paintings like this:
(Tableau I, Piet Mondrian, 1921)
(Champs de Mars: La Tour Rouge by Robert Delaunay, 1911)
But it wasn't just paintings. The nazis also thought architecture was "degenerate". Stuff like this:
(A Bauhaus style building in Chemnitz)
(La Samaritaine department store in Paris by Henri Sauvage (1925–1928)
(Club Moderne, designed by architect Fred F. Willson and built by Frank Wullus in 1937 for John Francisco)
I am showing you because it is important to understand what they were calling "degenerate", and understand that Art in the West had been moving away from representing reality and into specifically NOT doing that for SOME DECADES. They had likely grown up with new styles of architecture that were a radical departure from all that had come before (Nouveau, Deco, Moderne, Modern, Futurism, Bauhaus), ditto with philosophy, paintings, clothing, even gender politics. The Weimar Republic was the centre of the cutting edge of queer rights and that was largely thanks to people like Hirschfeld, basically the first person in the West to say there was nothing particularly wrong with trans people and help them transition and live their lives to the fullest. He also wrote and advocated for the queer community, and kept a huge library (which was burned by nazis in 1933 during one of these sweeps for "degenerate art").
This is what they're calling degenerate. They're whiny babies panicking because THINGS are CHANGING and CHANGE is SCARY and I'm gonna make it stop by setting things that are different on fire. These are deeply unserious people that need to grow the fuck up.