I’m sorry but the the Iron Cross out side the use of a German military award IS a Nazi symbol.
I mean why believe someone who is jewish?
en.m.wikipedia.org
You'll note that the list, that includes apparently the pitbull dogs, features the Iron Cross as used by the Nazi regime (with the inclusion of a swastika inside) which is a very significantly different design from the iron crosses designs used before and after. You also failed to mention that it didn't exist as a decoration before 2007 nont because it was "problematic" but because, as a war-time decoration, it couldn't be awarded in peace time, so there was no need for it until the Bunderswehr started to take part into foreign military operations in 2006. And it's not a "new design", it's the return to the original design (an iron cross), not the Nazi one (with the swastika inside). It wasn't really seen as problematic since, from the end of WWII, people were allowed to wear the Iron Cross, using the model predating the Nazi one (with oak leaves) if they were awarded it without association with the Nazi regime. Context matter and being offended by someone displaying an Iron Cross as a nazi symbol, with intent of promoting Nazi ideals, is legitimate, but there is no evidence that the painting was made extoll the Nazi regime. It was misunderstood, but not an admission to being a white supremacist.