That's an interesting point, but it's not a simple issue. Some places have benefitted economically from being a cruise port-like many of the Mexican ports. People do shop there when they get off the ship. If you've ever been in Cozumel, you know that the streets by the port are lined with shops offering things to the cruisers. And people eat (and drink) in the port. Other cities, like Venice, have been overwhelmed by the cruise ships and are looking at limiting the number and size of the ships. I don't know how they compare economically to flying, driving and staying in hotels on vacation. It's easier to run the numbers on how many pounds of waste there are from a cruise ship, but harder to figure how much vacationers waste in other settings. Cruise ships have also offered a lot of employment opportunities to people from countries where there many not be a lot of jobs. It's a dilemma overall as to how we can vacation without putting strain on monuments, beaches, the environment, etc. I don't know that cruises should be stigmatized above other forms of travel.