It's illegal because it's taboo. It's taboo because we live in a society who have morals based on judeo-christian tradition. This tradition says that relationships must be monogamous so no sex with random people. Therefore its frowned upon to have multiple partners but the law can only limits prostitution because that's one of the few things it can have power over.
If prostitution was legal, because its potentially dangerous, STDs and all, prostitutes or their employers would probably need to have a license and occasionally receive inspections. Food vendors go through similar procedures to ensure that their food is safe.
If prostitution was legal, because its potentially dangerous, STDs and all, prostitutes or their employers would probably need to have a license and occasionally receive inspections. Food vendors go through similar procedures to ensure that their food is safe.