That's an interview with NPR reporter Keith O'Brien, and as much as you'd expect someone who works with NPR to be a potted-out weedhead, here's how the article opens: "Today, more users are in rehab, but drug use is on the rise, and reporter Keith O'Brien says the policy has made the problem worse."
The article then goes on to note that the number of drug users in treatment has gone up by 63 percent, while their population of "problem" drug users was cut in half. This is apparently a "problem" because more people were experimenting with drugs. Fewer people developed addictions and died, but more people smoked a jay or shot up a little heroin for the first time. It doesn't matter how clearly decriminalization benefits society; a lot of people will always freak out if it means more people trying, or safely using, drugs.
Note that the bullet points there say nothing of the fact that fewer young people are dying from drug use. What matters is that they're using recreational drugs. A certain subset of the population prefers "people dying" to "people getting high without great harm." A great case in point is the Drug Policy Alliance. Their big critique of the legalization of marijuana is that it would make it easier for more kids to try it.