The word "racist" is thrown around improperly. What "racism" really means is the belief in the superiority of one race over another. Theodore Bilbo comparing blacks to monkeys on the Senate floor is an example of the worst sort of racism; I use it to illustrate the point.
Donald Trump has worked at the highest level of multicultural business one can work at. His businesses are international businesses, where he has interacted with all sorts of cultures, and no one would have used "racist" to describe Donald Trump before his comments on illegal immigrants from Mexico.
What Trump was referring to in his comments is the problems of transnational gangs that go back and forth between Mexico and the US, and consist of criminals that routinely enter the US, sometimes going back and forth between the US and their country of origin. These are the folks who commit rapes, and engage in human trafficking, as well as drug trafficking. These are the folks that provide muscle for foreign drug cartels within the United States. And they are allowed to do what they do, to go from their country to the US, in some cases back and forth, because our border is ridiculously porous.
The real problem with illegal immigration isn't some guy working at a dishwashing or janitor job off the books that an American could possibly full; it's the real threat to public safety brought on by persons actively engaged in criminal enterprises going back and forth across the border:
http://www.scpr.org/blogs/multiamerican/2014/07/16/17018/transnational-gangs-how-the-central-american-migra/http://www.csmonitor.com/USA/Foreign-Policy/2012/1012/MS-13-gang-labeled-transnational-criminal-group-a-first-for-US-street-ganghttps://www.fbi.gov/news/stories/2014/july/the-transnational-gang-threat-part-1-joining-forces-to-meet-the-challenge/the-transnational-gang-threat-part-1-joining-forces-to-meet-the-challengeIs it "racist" to point out the threat to public safety transnational gangs pose? Is it "xenophobic" to be concerned about the ease at which these criminals, who are not seeking the American Dream, but perpetuating an American Nightmare, enter our country, and (even more alarmingly) go back and forth between the US and their countries of origin?
On border security, Donald Trump gets it. That's not racism. That's not xenophobia.