According to guardian.co.uk, civic leaders in Amsterdam have been driven to regulate the city's infamous red light district where the prostitutes have a union and smoking in bars is illegal... unless it's pot. Well, pot is technically illegal, too, but to say it is "tolerated" would be an understatement comparable to saying that gaming is tolerated in Las Vegas.
This is what happens when you try to cobble together a moral code with no center, no organizing principle and no transcendent, objective truth. On what basis do you begin to formulate the idea that this much prostitution is just grand and should be promoted as a tourist attraction, but that much crosses the line into indecency? The people visiting the prostitutes are bound to have a different perspective. By what moral authority are you right and they wrong?