Pooling risk disincentivizes people from making the changes they need to be healthier. And people not bearing the full cost of their decisions makes it easier for them to displace the negative consequences of their choices on others.

I bust my hump in the gym a few days every week because I want to age well - I make an effort to eat healthy food and now I gotta pay for an cookie addict who would rather slurp down medication than make lifestyle changes? Screw that.

I made my choices, I can live with them. Others make their choices, they get to live with their choices. If they get to take good stuff from me to support their bad choices, I expect some reciprocation.