I had an Alanon sponsor that once told me that the very basic definition of a disease is 'if not treated properly the sick person will die.'
The Big Book of AA describes the disease of Alcoholism perfectly. It's a 3 part disease of Mental, Physical, and Spiritual.
The physical side being Compulsion. In other words, when the Alcoholic picks up the first drink s/he cannot stop. They usually drink until they run out.
The mental side is Obsession, which means when the Alcoholic has been dry for a period of time, the obsession will return again and again and again. The thought that it's ok to have just one. When they pick it up the Compulsion begins again.
And the Spiritual aspect is their total Self Centeredness. Regardless of how their drinking affects anyone else around them, what any one says etc. the Obsession will convince them to get that next drink.
As an Alanon I have been able to relate these 3 components to my behavior as a codependant.
Do you have to accept it as a disease? No, that's not what step one says. Step one for us is admitting we are powerless over the alcoholic and that our lives have become unmanagable. Am I powerless over the alocholic and is my life unmanagable? HELL YES!