Why are cigarettes sold at gas stations where smoking is prohibited?
For the same reason that liquor stores sell liquor. Profit. You can’t stand around in a liquor store drinking your purchase either, although that is generally a state law issue whereas any prohibition against smoking near a gas pump is by order of the fire marshall through local ordinance. I’m sure you aren’t allowed to buy a television at circuit city and start watching it in the lobby, either, but that’s just plain common sense, not a judical matter.