Nothing racist whatsoever. We have a group of people in our country illegally, often living in squalor in canyons and undercutting legitimate employees and contractors. We have a government which does not represent its citizens and at the behest of big corporate contributors is essentially looking the other way rather than enforcing the law.
Americans have a long long history of being addicted to cheap labor and exploiting those less fortunate and generally foreign and dark skinned, so in that regards hiring someone because you think they are Mexican and will accept poor working conditions and a less than going rate IS Racist.