If someone says their service on a cruise was so bad that it didn’t deserve any tip, I would wonder if they were actually on an RCCL cruise.
Sure they can choose to withhold any tips but...
The justification to totally withhold tips is based on a totally self centered ego where everything is about me, myself and I. Many folks, however, live by a different standard that involves love, concern and care for one’s neighbor, be they a room steward from the Philippines or a waiter from Indonesia.