God works in mysterious ways.

Fat people are fat, for the most part, because they are gluttons. Majority do not have medical issues, they just can't control themselves and they wont exercise.

Why should they be covered if they have no medical issues that cause them to be obese, or at the very least contributes to it?

If a fat person wants to lose weight it's easy. Stop consuming 5-10k calories a day. It's proven effective.