I have wondered about this too.

George Will poses a question I have wondered about for some time, but he does the posing in a most Georgewillian way. The guy has a way with words.

It is mysterious why states or localities that want casinos operating nearby -- and providing jobs and tax revenue -- also want them afloat, a few feet from a riverbank or ocean shore. (Mississippi has just decided to let them come ashore.) Does the narrow band of water provide a prophylactic against sin? The communities already have weighed the sin against the jobs and revenue and found the sin congenial.