This may simply be my own ignorance, on the matter, or perhaps a symptom of a failed education system, but I saw another one today, and I said I would finally ask about it.
When I see the Iron Cross, I immediately think of WWII, with all the classes, books, and documentaries on it, it's hard not to. Subsequently, when I think of the Iron Cross in WWII, it is always adorning Germans (obviously) and the Germans also wore the Nazi Swastika.
So, whether I see a Nazi Swastika or an Iron Cross, I think "Nazi Germany."
So why is it that the Iron Cross is an acceptable "decoration," if you will, it is worn on leather jackets, put as a sticker to adorn cars, etc... Whereas the same open treatment of the Nazi Swastika would be seen as deplorable and unacceptable?
(If this is the wrong subreddit, please let me know, and I will seek out answers elsewhere)
My personal experience does differ from yours in that I have seen people get flak for using the symbol. In any case, it undeniably has more public usage than the swastika. This is because the swastika was an explicitly Nazi symbol, while the iron cross had been the symbol of the German army since the late 19th century (and the Prussians long before that.) It was used up through WWI, then reintroduced in WWII. It continues to be used today in the Bundeswehr logo.
[I kind of only expand CommodoreCoCo's answer]
The Iron Cross, of course, is much older than the use by the Nazis.
However, it is quite linked with the Nazis, because a) the Iron Cross as a medal is freaking iconic (being black and beginning with the first class worn apart from other medals) and as such good to use in Movies (and how many movies have you seen about the Franco-German war? Or the Befreiungskriege?), b) the symbol of the Wehrmacht is something similar and c) the Nazis simply gave out half of them and a lot of their senior officers had theirs from WWI (Btw, who do you know who's got an Iron Cross in WWI? You all are saying Hitler, right [And Guderian, and Rommel, and Göring, etc.]).
The Iron Cross was established by Friedrich Wilhelm III of Prussia, in 1813, when Prussia was fighting Napoleonic France. It was meant to be given to anyone deserving, officer or soldier or even civilist. The design was chosen to be frugal. It was made of black cast iron, and interestingly, the 1813 edition was completely blank on the front. The back of the second class had a design with a crown, the initials FW a leaf of an oak, and below, 1813 (this is the design of the front of the later crosses, with the initials and symbols and years changed). It was worn on a black and white ribbon. The form of the cross came from the cross of the Deutscher Orden (Teutonic Order), which sometimes was depicted in that fashion (the insignia of the order today is changed). Maybe it's good to know that the duchy of Prussia was made from the territory of the Deutscher Orden, when the order disbanded/ partly went protestant, the last Hochmeister became the first Duke of Prussia.
Anyways, after the Befreiungskriege (the German part of the wars against Napoleon), the Iron Cross was seen as the symbol of the victorious Prussian Armies. The statue on the Brandenburger Tor (the Quadriga) was taken by the French in the Napoleonic Wars. When France was beaten, an Iron Cross was put in the laurel wreath sometime after 1815. (And a Prussian Eagle was put on top of that, maybe you've seen something similar by the Nazis?)
It was renewed by Wilhelm (later the I. of Germany) for the 1870 war against France, this time the date and name was on the front. The Iron Cross featured prominently in the insignias of the Kaiserreich, for example in the war flag, the marine flag, the flag of the Emperor etc.
Wilhelm II renewed the Iron Cross for the first World War. It was given out generously (compared to 1813 and 1870). Some five million were awarded, mainly second class.
After WWI, it featured the flag and insignia of the Reichswehr, the military of the Weimar Republik.
Then, it featured the flag and insignia of the Wehrmacht. The Nazis reestablished the Iron Cross, this time with more classes. It's estimated the Nazis gave out nearly five millions, again the main part second class.
After WWII, the Bundeswehr made an Iron Cross it's logo.
TL; DR. It's a symbol for the Prussian Army and the German Army, not the Wehrmacht in particular.
