Most people don't think about the effect this would have on the economy. They only think about their own bank account.
I'm not interested in dying to improve shareholder value. I'm not interested in spending a month in quarantine to do so either.
Dying is a bit extreme here, considering the mortality rate, whatever it is, of COVID-19.
And it's not just shareholder value. Believe me, Disney will be fine if they have to shutter the cruise division. Heck, they could eliminate it altogether if they have to. however, if the travel industry grinds to a halt, unemployment will quickly rise to double digits from other losses - port jobs, support jobs, tourism jobs. It's not just banning ships leaving US, but also ships coming to US.
Most people affected don't have resources to keep their lives going, so purchasing power plummets, bankruptcies increase, along with everything else that comes with loss of income (and health insurance). Things like bans increase a sense of panic and call into question the safety of other similar options. If cruises are banned, why not air travel? If people from these countries are banned, why not these other countries? Why is WDW safe if the cruises aren't - not just the parks, but the resorts and restaurants, too?
I fully support companies giving no-cost options to customers who want to re-arrange their plans, but blanket bans need to be thought out carefully. There is much we don't know about COVID-19, but it's not ebola and mitigation factors can go a long way to ensuring guest safety.
There is a lot of unknown here. We have to respond carefully so we do't create other problems that will shift the damage or cause more of it.