"If I focused on my health, ate clean and exercised daily, why should I also be subsidizing Billy "video-games-are-my-exercise" fatass's chronic health conditions?"
This is why there is a hyperfixation on shifting blame away from (failing) individuals. The logic breaks when Billy has to admit he just hates exercising.
And yes, before you comment, I know "maybe Billy has (condition outside all control) so it's not on him". Please, see what I just said in the previous statement.