Conspiracy ..naw. Open borders, probably. Which seems to be what the current White House wants very badly.
The thing is is that the Mexican-Americans (the ones who want to allow more illegals into the states) don't seem to understand that by letting in Mexican nationals, their own jobs may be threatened. Illegals will work for lower wages (usually cash only) and/or little or no health insurance. The American citizens, of Mexican decent, are being aced out of some fairly good paying job here in California. A lot in construction jobs, which can pay $50,000 a year (with benefits)and up. Advantage being, that paying a much lower wage, with no benefits, means more money for the employer. Even skilled jobs like driving heavy equipment, welding, framers, etc are taken up by cheaper labor. Just go by any construction site and notice very few white or blacks working on them. Other point that American blacks are overlooked for most of these jobs.
Little secret is that Mexican nationals do not think very much of American-Mexicans. And are happy to replace the Americans on any job.