Somethings in life are Adult Privileges and Resposibilities. Gambling is one of them ... so are drinking, smoking and driving. It is up to each adult to be responsible for such activities.
I enjoy gambling, but I do it sensibly and responsibly. There is no more evil in this than in any other human activity, because done to excess anything can be EVIL.
Now that I have that off my chest -- enjoy your cruise and any activity you choose to do.