I see; I was not aware that there is a specific connection between Nazis and the "brownshirt" term, though it is obviously a reference to some kind of uniform.
I genuinely appreciate and commend your honesty about the fact that you didn't previously know that.
Separately, it's an unfortunate that even on this forum, the term Brownshirt has been watered down to the point that it's lost its Nazi association completely, much like other Nazi terminology that has been rehabilitated in recent years.
A Google n-gram comparison of "nazi" and "brownshirt" shows the latter to be vastly rare compared to the former.
I just compared several terms associated with the Nazis: brownshirt,wehrmacht,luftwaffe,hakenkreuz. Their popularity is in the same ballpark.
Luftwaffe is showing a strange resurgence, having overtaken brownshirt.
Brownshirt was on a popularity rise since 1960, but has declined recently. It is now only about 3 times more popular than hakenkreuz, though, which I would think is pretty obscure.
I think people tend to be relatively reluctant to do a dictionary lookup on a rarely heard word that is made of two everyday English words like "brown" and "shirt" and which is easily explained as a fairly obvious metaphor.
...Uh huh. What, exactly, did you think it meant? You clearly had something in mind.
:-o
It also seems that a two-word form Brown Shirt also saw some use (in reference to the Nazis).