I do not assign credit or blame for disease to God. Saying that it is within God is one thing, asserting that he rewards or punishes with it is something else indeed.
It is called Vanity. Taking on oneself the authority to define God. It is the greatest of sins.
God did not create HIV. And He rarely uses disease to punish the sinful (which includes all of us). But when a community shakes its fist at the Almighty, like the porn community, He very well may use disease (or pestilence)to punish the defiant sinners.