migration and overpopulation

When i came across this picture, i halted at the artists work. Then read that it was his interpretation on migration and overpopulation. The more i looked at it i understood. if the US started excepting huge amounts of migrants then our country would be overpopulated. most of the migrants that are coming in from the south are laborers that would contribute to the lower end jobs since they aren't legal. even if they were doctors in their country, they would have to past exams in the US and therefore reveal their illegal status. so then there would just be a lot of migrants fighting for under the counter lower end jobs, trying to improve their lives when really they turn into more mouths to feed in the economy-hurting the US.