Why are the union workers work so unimpressive ?

One of the example is the WTC towers, it collapsed before you can cat in a hat just cause some dudes rammed few aircraft on it, it's as if it built with paper, the only thing to blame is the bad craftmanship of the union workers, who built it and these mofo formed a gang and recruit the worst dudes prossible and they keep rioting on street demanding for more right and more money, what happened to supply and demand man!