However by 1939 it ended up on the list of songs which were banned in the third reich. It suddenly was branded degenerate music along with music from Jewish composers and Jazz music. The reason why it fell out of favor was because it was seen as kitsch and it was also perceived as a satire on Hitler. It took them 6 years to figure that out.
Reminds me of right-wingers loving Rage Against the Machine and then turning on them as "woke" when they discover that they're part of the machine being raged against.