While the article makes it clear that Powell now regrets authoring The Anarchist Cookbook, it is also made clear that the reasons for his regrets are far more interesting and nuanced than the quote above would have you think:
"When Powell was in his late twenties and teaching special-needs students in New York, he returned to White Plains High School. At the school he had struggled academically and socially, and looking through his results from two intelligence tests, he found what he took to be a clue to his unhappiness. “There was a huge discrepancy between my verbal and performance I.Q.,” he says. “That would have been a clear red flag in today’s world that something was going on. But at that point in time, nobody paid attention to it.” Powell thinks he likely had a learning disability of some sort, which contributed to his trouble in school, his alienation as a young adult, and his current work to support learning-disabled students."
Powell spent the rest of his life trying to help frustrated young people like his former self, which is far more profound and noble than an old hippie selling out.