I have no reason to think that those shantytowns are inhabited by Hispanics. But you are right that Maryland, and particularly Montgomery County, has rolled out the red carpet and made the embrace of illegals a formal policy.
Do you have any idea how many times I, a white lady with considerable knowledge, experience, and talent in the care and handling of horses, got turned down for rough farm jobs in favor of Hispanics? Farm owners believe that Hispanics will work without complaint and will do a task for very little money. They seem to prefer to have Hispanics clean reeking stalls and do manual labor to black or white American citizens, for the same money. There is a widespread misconception that Americans are lazy, though your average middle-aged American has a highly developed work ethic.