most preschool programs are 3-4 hours several mornings per week. if these kids can't behave in that setting for that amount of time, it is their parents fault for failing to discipline them.
The article is lumping public-school "Pre-K" programs, day-care centers, and who-knows-what-all together.
I agree that children need to be discipline, but I don't think school is the right place for 3-year-olds.
You would think, if lack of discipline is the basis, that you would see girls as well as boys expelled. Maybe misbehavior in boys tends more toward physical outlets that cause greater disruption to a classroom, while girl misbehavior is less disruptive on a classroom level? Or boys, due to their natural inclinations, more noticeably display the results of poor discipline? I think the best preschool for my boys is going to be one with an outdoor playground and lots of physical activity... I notice my older son's behavior is a lot better when he's burned off some of that energy.
Bingo! Some kids need a spanking. Like when defiantly ignoring a direct "don't do X" instruction from an adult.
Perhaps, Mom need to spend more time with little Kevin teaching him how to behave.