I dont want random heavy metal or whatever these people were talking about.
But I dont think having music would ruin the historical aspect of the game. See my suggestion about era appropriate music such as coming from radios on the maps.
It is also true if one doesnt like the music one can just turn down to zero. Id just add that there should be a straight On and Off switch in settings for music to make it even clearer.
It’s really a big surprise to me, how popular the Panzerlied is around the world. Thanks for enlighten this to me! 
Yes, both were removed from songbook (and many more…) and singing them will get you into trouble. It’s not even important, what’s in the text, when the date of origin is after 1932.
But enough regarding this topic for now.
I agree with you and as someone who enjoys (not only german) military music I would love to have some more, at least in the hangar.
Greetings to Australia from Germany!