They are calling them "migrants" to hide the FACT that they are illegal aliens. "Migrants" makes it seem like a nice visit by people from another country. The true migrants in the U.S. are the farm workers who get seasonal visas to work crops in various parts of the country, but are supposed to go back each year (but I wonder how many never go back), and presumably return the following year, or perhaps at a different time of year in a different part of the country.
They are calling them "migrants" to hide the FACT that they are illegal aliens. "Migrants" makes it seem like a nice visit by people from another country. The true migrants in the U.S. are the farm workers who get seasonal visas to work crops in various parts of the country, but are supposed to go back each year (but I wonder how many never go back), and presumably return the following year, or perhaps at a different time of year in a different part of the country.