I'm always up and down on this. If anyone has ever had to sit through watching someone they cared about go through alcohol withdrawal, it is obvious that there is a real physical component to addiction that cannot be denied.
As Justfor1 said, there's a behavioral component in there that makes it difficult sometimes to accept that the person can't help it, as they claim. It's also grating that so many so-called "recovering" alcoholics blithely dismiss the pain of those they've harmed with the notion that the hurts simply shouldn't count because what they did was, after all, just part of that silly ol' disease. With some of their rhetoric such as "there are no victims (of alcoholics), just volunteers", the people on the receiving end of the alcoholic's bad behavior are led to believe their feelings are not valid--and once again, same as it ever was when the alcoholic was actively drinking, their feelings and priorities and lives are shoved aside in favor of the "poor sick alcoholic", who, after all, just "couldn't help" lying, name-calling, or worse.
I think that this attitude of not having to be responsible for one's behavior in the recovery culture goes a long way toward unacceptance by the drinker's family and friends of alcoholism as a disease.