It sounds like a joke that fell flat. Happens sometimes.
Maybe I am over sensitive to these things? Maybe it is just how members of Red Sox Nation react to seeing my Yankee hat. Let me tell you these two stories. I checked into Pop Century without a problem. Later on my parents arrived and I went with them to check in. The worker seeing my hat says, I really don't want to help you, but its my job. At one of the restaurants, there is a carving station, the lady with the carving knife looks, sees my hat, says nice hat, can I have it? Before I can say anything, she produces a lighter from her pocket and says, I want to burn it. And these were Disney employees where other companies send their employees for customer relations training. I can tell you dozens of other stories.
The bottom line is this. When you are working with the public in any job, you keep your personal prejudices out of your job. Maybe some Yankee fans react the same way to seeing the letter B on a hat would be wrong also. Sports prejudices should be kept out of the workplace when dealing with the public.
Bruce-SSR
It's also wise to keep in mind that there are a range of ways of thinking out there. I am a very literal-minded person, I tend to take things said in jest literally. (I also experienced a lot of peer-rejection as a kid, and I'm sure that colors my way of reacting to people). I just in general deal badly with "friendly" teasing because for some reason I have a hard time parsing out if teasing is 'friendly" or "hostile." I don't know why. (No, AFAIK, I am not on the autism spectrum.)
If someone harassed me for wearing whatever SportTeam thing I was wearing, even jokingly, I'd be taken aback and think, "Wow. They really don't like me, just on the basis of how I'm dressed." And I'd feel weird about the person the rest of the trip, maybe not ask for help when I needed it. Maybe not even tip as well, I don't know.
If someone smiles or makes a laugh after making a comment, then its friendly banter, and should be treated as such. But if someone says, I really don't want to help you, but its my job, no smile, no laugh, then its hostile. Remember, the SCA I mentioned took a complaint from a fellow passenger about this Yankee fan by saying, I feel the same way. No smile, no laugh, but dead serious. I am pretty much a low maintenance person, I will lower and raise the upper bunk by myself if allowed.
Being in the customer service industry, interfacing with the general public, if you find a hat offensive to see, then you bite your tongue, or look for another job.
Just FYI, I did give my usual tip, its just the type of person I am.
Bruce-SSR