You are dead wrong. The sojourner is fully subject to the laws of the nation in which he sojourns, and if he breaks those laws, then he forfits his rights. That clearly is the Biblcial position.
If they look at everything God has to say about thieves, it can be applied to illegals, too. Different picture, then. Especially when one realizes that not all illegals are mexicans. The arabs come to steal, kill, and destroy.