Yes a very interesting question...
I can only speak for myself and it has nothinng to do with who won the war or any political, racial or ethnic reasons.
Simply put, I have always been impressed by the advanced aircraft designs of WW2 Germany, hence my interest in Luft 46.
In fact many aircraft of today have been heavily influenced by these concepts. In the majority of cases, what you see flying today has at least some small detail found on a German design or a development of.
Plus many of the German aviation designers were employed by the various allies after the war, to continue their development work and research.
Also David (spooky6) hit the nail on the head ...German stuff in particular offers so much variety in colours, markings and camo schemes and patterns, that makes each model eye catching for these reasons alone.
Having said that I am also equally interested in British, American, Russian and Japanese aircraft concepts of the samne period. Its just that there is a lot more German material to go at.
Cheers
Peter
:-)