Isnt drug addiction based on someone's impulsivity and them giving in to that impulsivity?

Yes, it is stupid to get hooked on drugs in the first place and I am sure no one INTENDS to get addicted. Once we are addicted, it takes massive determination to get clean. 

As someone who managed to give up smoking (which is just another drug addiction) I would never belittle the far greater effort required beat things like opiate addictions or crack cocaine addiction. Once you are addicted, you lose the ability to think rationally about your addiction. It becomes a compulsion you cannot resist.

That does not mean we should treat drug addicts as victims or make exceptions for them.  It does mean we need to be firm in our treatment of criminality caused by the need to feed a drug habit. 

Our priority should be on breaking the supply routes so drugs cease to be available on our streets. The smart, partying, weekend cocaine users are part of the problem as they help finance the filthy drugs trade.

Most addicts hate themselves.  It's why liberals take so many drugs.