Any public venue is vulnerable. There are a million ways to attack unarmed citizens at any location. Cruise ships do have better processing and security screening than airports. Some have response teams, some do not. In Port, you’re generally on your own, but that’s true anywhere.
I love traveling and cruising is one of the most relaxing ways to travel. I’m not changing my life to accommodate terrorists or fear mongers. I would prefer to carry onboard, but that would also ease getting weapons onboard. Life is about risk and reward. One can live in a bunker to be safe or take a vacation in Syria for excitement, but most people prefer something in-between.
I think the cure is to not be unarmed and to have a plan for any place that is vulnerable.
I have my vacation home in a stable country that does not permit any Muslim nonsense and I can stay there if things go south in November.