Limbaugh was making a point about an obvious and shabby lie, not a point about drugs.
In addition.........Any comments about Klinton were aimed at his "recreational" use of a drug; Rush's use was "medical", that turned into an addiction.
I'm still wondering what he will do for the chronic pain he's experiencing from his back injury. Even if he 'de-toxes' from the current highly addictive pain killer, he will still have to be taking something for his condition (Yes?).
Initial motivations are not meaningful. The end result, addiction, is identical despite those initial motivations. Rush's success depends, in some part, that he does not try to distinguish between Good Dopeheads and Bad Dopeheads -- and try to brand himself a Good Dopehead.
All Dopeheads are equal in the effort to recover.