I think some of us are closer in viewpoint than we imagine, and really just arguing semantics.
I call it a disease because, clinically speaking, that's exactly what it is. It meets the definition.
That doesn't take personal responsibility out of the equation. Just as poor diet & exercise lead to diabetes, alcohol intake can lead to alcoholism. They're both still diseases. And they both can be either prevented or helped by direct personal action.
In my own recovery, I recognize that alcohol has had a direct, physical, measurable affect on my brain & nervous system which reinforces addictive patterns and makes long-term abstinence difficult. This is part of a disease process. But that knowledge doesn't give me a free pass or excuse - unless I'm looking for one. I use that knowledge and understanding instead to work towards my goal - sobriety. That's personal responsibility in action.
The reason I feel classifying addiction as a disease is important is because it underscores the reality that willpower alone is not the answer to abstinence. Because it's not. The mechanism of addiction are far too complicated & powerful to be solved with willpower alone. When you eliminate the term 'disease', all you're left with is 'choice'. And anyone who's ever been addicted knows that quitting is far from as simple as choosing between coke & pepsi.