Stupid has nothing at all to do with it and certainly not the color of their skin.
Ok, so you pick up on the job training, in the meantime (while you are lying about your skill level) you are building a wall without things such as expansion joints, vertical rebar, horizontal rebar, corner rebar, that oh, I cant see it from the outside so I didn't know it needed it kind of things. Probably wont need it really, unless there is an earthquake. When that happens, well, don't be inside the building.
When I entered the masonry trade I really had an elitist attitude about it. I was an honor student in high school, kicking ass in college, gf got pregnant, felt I had to do what a man does. Ended up married with a baby and a full time job. I thought laying brick would be mind-numbing at best. What I found out was you need every bit of 4 years apprenticeship under a journeyman bricklayer to learn everything you need to know to do it. Even then you are still learning years later. What happened in many cases were group hirings. Illegals skip that training or get a few months at best, then branch out and claim to be a journeyman. There are bricklayers in other countries, don't get me wrong. But, there are huge differences, including material. A block/brick in (let's say) Mexico is not the same as a block/brick in USA. They are made from different materials and layed different ways.
Anyway, stupid has nothing to do with it. In many cases, illegals are go-getters but they skip a lot of steps and never really learn their crafts. Why spend 4 years as an apprentice when they are hoping they can make enough money to go home in not much longer time than that?