This article is kind of simplistic in its complaints and I think it hurts the intended cause for that  reason.

For one example, there are many many reasons to dispute the rampant use of Ritalin, but making kids "go postal" isn't one of them. More like the opposite. I personally know that Ritalin's intended effect on hyperactive children, and many years of use has shown it to have this effect, is to calm down bad behavior. Though I wasn't mature enough to pay detailed attention to how the decision was made at the time, I do recall when it was finally decided to give it to my developmentally disabled brother: after an incident when he got up from his chair in the middle of class in like 2nd grade, and then proceeded to hit each of his fellow students on the head with a pencil, and wouldn't sit down. That was the last straw for a teacher who couldn't get him to listen to a word she said, he was apparently just too distracted/excited by being with a large group of kids to even be able to sit reasonably still.

He got calm and focused on it and could be taught. He graduated from high school with its help, reads and writes and does arithmetic pretty well despite a very low IQ.

Most complaints about ritalin use with kids are more along the lines that it takes their passion and excitement and creativity and independent thinking away, while making them more obedient.