There are a number of stewards and waiters who will give you the story that they don't receive their gratuities. This is B.S..
I have spoken about this with Hotel Managers and long time waiters and room stewards and all of them have said that they receive their tips.
One long time steward we had on HAL Statendam spoke to me about this when I asked him how he liked the automatic gratuity vs. the old system "Tipping is not required" policy. His answer was: "I love it". He went on to say that many people would think that "Tipping is not required" meant they didn't have to tip at all and he would receive nothing. He also told us about the people who remove their automatic gratuity and say they want to tip in person. The vast majority of these people never tipped "but" the people who did tip gave much more than the recommended amount.
About ten years ago NCL did a study about people who remove their tips and say that they prefer to tip in person. Their results were the same as what the HAL steward told me. Over 80% of them never tipped and used it as an excuse to stiff their service staff.
Regardless if you approve of tipping or not the fact of the matter is that this is how the system is set up and not tipping only hurts the people who serve you. If you don't like the system let the home office and senior staff know it. Don't do the passive/aggressive thing and just stiff the service staff.