You can argue all day about the positive and negative aspects of using Marijuana. You may even succeed in legalizing it's use and possession in the USA.
At the end of the day, it really makes no difference.
Cruise ships must still ban it to avoid the Captain getting arrested and the ship detained in over 100 countries.
For the past 20 years we have been trying to get service dogs legalized in all those countries. There are still more than 20 that will not allow the dogs to enter their country.
How long so you think it will take to get marijuana legalized in all those places?
Instead of these pointless arguments on a blog site, perhaps you should re-direct your energy and start writing letters to the UN.
Or maybe start an American cruise line that only visits countries where marijuana is legal?