It says it in your cruise contract. If it's because of weather are you willing to gamble that nothing will go bad if Holland doesn't cancel those ports?
How about the
Crew they have family, this is how they earn a living
Guest Entertainment
Other guests besides you on the ship
The ship is worth $$$$$
The next cruise after yours
If there is a place in the World you really want to see, and will be upset if a Cruise ship skipped those ports, don't take a cruise to see that place. Fly in. There are places in the world that a cruise ship might have problems getting guest there. It happens often.
Sorry you didn't know this.