Developers are a big problem in large cities. They buy up properties in bulk, build larger townhouses and condos; and turn a huge profit by charging higher prices for less land. The phenomenon of immigrant families packing into houses is significantly less impactful than developers packing dozens of families into land that previously held a few smaller dwellings.
Stop the focus on poor immigrants -- they aren't stealing your money and land. That's what rich developers do, and much more effectively than immigrants could ever muster