Americans, we are all about freedom. Freedom to kill ourselves and eat twinkies. But we expect help when we are sick.
One side or the other has to budge a little. Do we give up being able to get the same insurance despite unhealthy habbits? Do we give up helping the poor and the sick?
Go skiing? Well there's a higher tax for the ticket because you have X% higher risk of breaking a leg. Twinkies right now are a grocery food so in fact it has less tax, where it probably should be taxed like booze or cigarettes (in effect a sin tax). Of course sin taxes get abused, where the money goes to the general fund rather than going to mitigation for the undesirable behavior.
I think for most things we are too stupid to really calculate the extranalaties of products.