They have no practical skills or affinity for the profession they are trying to enter (I've heard more than a few say they would prefer working in IT after getting a "CS degree" because "programming is hard and boring").
IMO the problem comes from "government programs to fill demand from IT sector" and the converting college to high school 2.0
When I went to college you actually had to pass entrance exams and people avoided technical colleges like plague if they actually weren't interested in them - this is still true for top colleges in EU - but the trend of pushing college as a ticket to a comfy office job obviously doesn't result in a bunch of highly skilled professionals (reduced standards to allow greater number of graduates) and gives you a bunch of people who have high expectations and no practical skills - so you get angry kids on the streets.