It’s not medical advice, it’s an opinion. And he’s right. It isn’t a “disease”, it is a weakness, a personal failing. You can blame the alcohol or the drug, but in the end, people choose to do what they do. Any recovered alcoholic or drug addict - the honest ones, anyway - will tell you that they, and they alone, were the cause of their addiction. Calling those things a “disease” implies that the addict is a victim of something over which they have no control. And that absolves them of their responsibility. Animals have no control over what they do, but people do.
How is addiction in any way a disease? Seems like a very convenient excuse, but words still have meaning.
Alcoholism is not a disease. Drug addiction is not a disease. They’re a lifestyle choice.