That is my pet peeve too. I have to confess though, I used to be one of those uneducated in MA people who thought all martial arts were called Karate or Kung Fu or Tae Kwon Do.
Soon after I started Aikido, I began to realize the vastness of the MA world and how different the styles and arts are! But now it really bugs me when other people keep calling Aikido "Karate" (Karate is a wonderful art and I have nothing against it. I just wish people understood how the arts are different. Especially since Aikido is SO different from Karate from what I've seen and done!). 
(Our teacher explained color didn't matter for the above reason, then told us all to get black because it doesn't get as obviously dirty as quickly. ) I'm sure that if people insisted on calling my art something it wasn't, espcially after I told them what it was, it would bug me, too. I can't recall getting that from the people I've talked to though. As a sort of aside, I do like having a forum like this where everyone studies MA (or at least has an intelligent understanding of them) to talk to. And with all the different arts represented, it gives a variety of viewpoints which is always helpful.
