Vikings are a people who don't really exist any more (you could make the case that they still exist in Iceland, but...that's not a strong argument), which makes it a lot less odd feeling. Fighting Irish IS fucking weird, to the point where I assumed it was a nickname before I googled it right now. Browns, technically, is closest to the 'creature' category.
Overall though, you're right; there WILL be exceptions to this. An exception or two over the entirety of the sports world doesn't suddenly make something not unusual though, you know? My point is that everything aside, its a really odd name - and that's before you factor in the problematic history that its trying to cash in on.