Video: The Wave Ad. How is that racist?

The problem of illegal immigration in the border states is different from that of the entire US;  it is focused on a specific ethnic group, the Mexicans - the people of the bordering country.  So, how is this ad being racist?  If it showed the Chinese, then I agree it would be racist because their percentage of illegal immigrants is less than 1%.  So, in my humble opinion, the ad is being factual.  Of course, the Democrats will always impugn albeit unfairly.  But judge for yourself.  If video fails, go to http://divine-ripples.blogspot.com/2010/10/video-wave-how-is-that-racist.html