This is difficult to answer in any concrete way, but for what it's worth, the United States Holocaust Memorial Museum in Washington has several examples of Nazi uniforms in their permanent exhibition. You can see their guidelines for donations here.

I feel like getting one of those would make their day due to it's historical significance.

Yeah, you might expect this, until you realize how common those uniforms are. They are a dime a dozen. Remember, there were literally ten of millions of "authentic" Nazi uniforms produced, hundreds of millions if you're willing to count combat uniforms. And we're not talking about ancient history here either. There are people who would have been old enough to wear those uniforms who are still alive today.

To the extent a reason for the fictional curator's disdain can be guessed at, I would suggest that the issue dealt with the concept of buying the uniform, as opposed to having a Nazi uniform in the collection.