First of all, I do agree that some are more prone to addictions than others. I have a friend who can get a strong habit out of just about anything. But I strongly object to calling it a disease.
For instance there is billboards promoting stomach surgery saying “Overeating is a disease, not a choice!” The implication is that it is not your fault for you addiction.
A habit can be very strong, but that still has an element of will in it.
What you clearly fail to understand is that the natural inclination of an alcoholic's will is to drink. It's a common misunderstanding that an alcoholic "has little or no will." The fact of the matter is, if you lock up an alcoholic in prison, he'll find a way to ferment fruit in a commode. An alcoholic will risk family, career, freedom and life itself in order to drink, and in fact, many fall into despair because they can not overcome their will to do so.
The drinking itself is a symptom, not the dysfunction. Many alcoholics do become "dry drunks," and while they "resist" indulging their "habit" (as you call it) they still suffer from many other unsettled aspects of alcoholism.