Stung, I think that's a really good analogy with diabetes that I have never thought about.
Alcoholism might be a disease, but the wait it's managed (never cured) is that the alcoholic at some point chooses not too drink.
So getting back to the original post. Yes I think your sponsor is not correct at all on WHY/IF you should feel compassion. You might feel compassion for their struggle to remain sober, but in the end it's their choice.