They come here because we invite them and they are desperate. They have to go through pure hell to get here. Most of them would like to work a while and leave but their nation has turned into a narco-terrorist oligarchy and they will be robbed trying to get home.
I know these people are desperate. So are billions of other third worlders. Does that mean to you that we should let each and every one of the in and give them free health care? How do we survive as a nation with such a philosophy?
Mexico is well-off in terms of public health and per capita income when compared to most third world nations, so why do we give preference to its people? If you want to be Christian about it, you'd reward the people throughout the world who are being honest and applying for legal residency, and you'd also be in favor of giving the most needy the first shot at available jobs.
You're wrong about us inviting them, they are invited by their illegal kin and friends. Most of the illegals are coming here to look for work, they don't have the job already secured. They have some friend, family member, or consular employee who is going to put them up and get them off on the right foot - you know, get them their fake IDs, show them how to enroll their kids in school and free lunch programs, and how to use the ER for everything from a hangnail on up.