[kennywinker]

Agree up to "type 2 diabetes doesn't seem to have an impact on ability to pass on ones genes, so natural selection would be blind to it."

Individuals who have extensive family support do better than ones who do not. That's why we don't die the moment we stop being able to produce offspring. Grandparents care for grandchildren, and help pass on knowledge that is very helpful for survival.

So not blind to it. Reduced impact, yes, but not blind.