That's only true if you believe that there isn't some fundamental part of this business that is profitable and market forces won't eventually lead to new cruise companies popping back up in the future
In this case, I'd say we'd be better off letting that fragility run its course.
Very few (if any) Americans depend on the existence of the cruise industry to make a living or otherwise survive in our society. For the ones who do, it'd be cheaper to give them individual "bailouts". Cruise ships contribute jack all to the national or global supply chain except as consumers of it; letting cruise lines fail means more capacity on that supply chain for things that actually do matter (especially in times of crisis).
Even bank bailouts have a better value proposition, and that's saying something.
Trade imbalances aren't good for economies and eventually lead to wars 100% of the time. Read about the Opium Wars if you want a textbook example of this.
Yes, I agree the system should not be that fragile, but for now it is.