I think that the comparison is an apt one. Diabetes can be difficult to control for some, and easy for others. Some need insulin, some can take metformin, some dont or can't take these treatments for various reasons. Controlling it is not a guarantee of health or wellness, just as treating depression does not mean it goes or stays away.

They both have a chemical and psychosocial epigenesis, and both have contributing genetic factors.

I get why it would grate, because I know that I would not have problems saying to co-workers that I am having a diabetic emergency, but would not say that I was hospitalized for suicidality. But I think that it's actually a pretty good nuanced comparison and guide to understanding.