...that the revenue from sin taxes actually go to mitigate the effects of the sin. More often than not, they do not.
For example, the revenues from the "tobacco settlement" lawsuits that were supposedly to mitigate the cost to states due to smoking are more often than not spent on boondoggles:
http://abcnews.go.com/GMA/story?id=125919&page=1#.UKTt1-S_B8E