I seen this happen with a lot of Mexican Americans, they dress up pretty much the same and they think that you have to like their music and to have this raza mentality in order to be a "real" Mexican, but this is mostly the fault of stereotypes, I´m a Mexican living in Mexico and I have met some exchange students such as Mexican Americans and Texans and most of them think that you have to act like them in order to be a "real" Mexican or Texan.
Also, I used to dislike the Mexican hat and mariachi look until I saw the movie, "A walk in the Couds" and I felt proud to be Mexican, the movie is about a guy who gets in love with a Mexican girl and he learns a little about the Mexican, Mestizo culture. Also, the Mariachi look is like the "Scotish pipment" outfit of Scotland and the "Lederhosen" outfit of Germany, they don´t represent our daily clothing, we only dress up like that in celebrations.
You don´t have to read this but this is an article of how the "brownface" was created in the United States. http://brown-face.com/
A Mexican diplomat that is tired of Mexican stereotypes.
http://www.forbes.com/sites/doliaestevez/2013/09/18/mexicos-ambassador-blasts-hollywood-for-promoting-racist-stereotypes/
In the past, when Bruce Lee first came to the United States, the American television was constantly making fun of Asian people by stereotyping them as if they had big teeth and huge cheeks in an exaggerated way, but Bruce Lee helped change that image, we need a Mexican Bruce Lee, in other words, we Mexicans have to change our image and I have seen offensive videos like "Capitan Mexico" in Youtube and when a Mexican says that he is offended, other Mexicans say that this is just funny and nobody should say anything which means that when someone makes fun of us, we just laugh with them instead of trying to change our image, so we are doing this to ourselves.