I've heard the term 'Mexican-American' long before it was considered a 'PC' term or fashionable to hate on PC terms. It just 'is'. Not seeing why it's considered a derrogatory thing.
It's like this. Why do you need to thow the "Mexican" in there? Unless you are of native (american) descent then your family line obviously isn't originally from the US. Throwing another country in there is either saying "I am an American, but not really" or "I am an American but I wish to seperate myself from all the other Americans for some reason."
It isn't derrogatory, it just seems to single out a group of people that don't really need to be singled out. If you live here welcome to the country... I don't give a crap where you are from originally.

Also there is a problem where people use such terms to "politely" categorize your race, not your country of origin. "African American" is the worst offender on that one. Your family is from Africa? Really, which part? Oh you don't know because your family line has been in the US for over 200 years and for a good bit of that you were slaves. When somebody calls someone an "african american" they mean "a black person" so why not just call them a black person? Like-wise when someone says "Mexican American" they generally mean they are brown skinned and are probably of latin descent. So why not just call them Latino or Chicano or whatever?
I'm of Irish, Scottish, English, Slavic and Cherokee descent, but when people see ME they just say I'm a white guy.
