Sessions is of course correct. There is absolutely NO STEM worker shortage. The opposite is true: there is a glut, made worse by the constant influx from places like China and India. And that's what this is all about: the desire by elites for cheap foreign - in the case of STEM, Asian - labor and the desire by the aliens themselves for opportunities in America and to increase their numbers while displacing Whites.
Flat wages and high unemployment are not signs of a "worker shortage."