I do wonder whether he has a point. No matter how much you ban things like this, people will find access to them and you risk promoting them by making them cool. It certainly seems to me that tobacco seems more appealing to those under the legal purchase age then those over it.
As far as I can see most of the issues with using these types of drugs effect the user rather than society as a whole, at which point is there not an argument that if people want to use them and they are aware of the effects, why not just let them get on with it if it doesn't affect the rest of us?
It seems to me that the only effective way of preventing people getting into these things is education rather than prohibition and legalising it would give government a lot more control over what is in circulation and help reduce the issues of cutting agents.
At the end of the day, I don't want to buy any, so it doesn't effect me, but it does make me wonder. Is this really the best way to discourage their use?