I was on this cruise and registered a complaint. This was the response I received from Norwegian:
I'm pretty sure that the bolded text is an untruth.
Thank you for choosing Norwegian Cruise Line for your vacation at sea.
Our primary objective is to provide our guests with a memorable cruise vacation from beginning to end and we are committed to providing exceptional vacation experiences, both aboard our ships and by taking our guests to some of the most sought-out destinations around the world. While we try to maintain original itineraries as much as possible, at times modifications are made to optimize the itinerary or to accommodate certain circumstances. To enhance the guest experience, the ship's current itinerary was revised to allow more time for guests to explore Stanley, Falkland Islands. As such, the cruise by Paradise Bay, Antarctica was replaced with a cruise by Admiralty Bay, Antarctica. In addition, due to a recent regulatory requirement in the area, the ship is operating at a reduced speed, also impacting its original itinerary. Under the terms and conditions of our Passenger Ticket Contract, Norwegian Cruise Line in its sole discretion may cancel, postpone or delay any port of call without prior notification. Therefore, we are unable to provide any compensation in this regard.