There's no question in my mind, if I was expecting a Bermuda cruise and went to Canada instead, I'd be disappointed. And everyone on the sailing has the right to be disappointed.
However, I would NOT have booked the cruise to Bermuda during hurricane season.
I've cruised several times during hurricane season, and have done so understanding that my itinerary may change. Somewhere along the line people do have to accept responsibility for their own choices as well.
If the itin. was the reason for booking these people should not have booked when there's hurricanes possible. They were gambling that things would go smoothly. They can't really expect someone else to pay for the gamble not paying off.