Not friendly to vegetarians

Wow. I sailed one week after you and found enough food to eat as a vegan. Granted I had to ask when in the Skyline dining room, but there was a person who handled special dietary requests and worked with the chef(s) to ensure that I had a substantial and tasty meal each night. We used the Aloha Cafe for breakfast; I found jasmine rice, vegan stir fried veggies, hot cereal with dried fruits and veggies, and fruit that was plenty to keep me going until lunchtime. My omnivore BF found more than enough options there. Our only complaint was the number of people who pushed, and young kids running between adult legs like they were in a video game. The BF said it was what socialism was like so we starting calling it the Bernie Breakfast Place. On our last morning we ate quietly in the Skyline, but there was not rice and veggies for me - only cereal.
I also purchased 8 oz containers of soy milk and brought them with me so I could have coffee in my room. I'd bring what was left with me to breakfast.
On excursions, one time we were offered a chicken wrap, which I couldn't eat. The guide felt bad and found me a protein bar. I had dried fruits and nuts in my back pack. and there were chips. I was fine and did not expect to find a vegan meal on a bus tour up Mauna Kea. On our Road to Hana excursion there were some fruit and salad options. Again, I had snacks in my backpack.
Vegans and vegetarians are still a minority so on excursions I do not expect to be considered. At the Luau on Kauai, there were a number of clearly marked vegetarian and vegan options and I left feeling quite full.
I was apprehensive at first, since when I called ahead I was told they didn't do anything special in advance so just tell the people in charge when I get there. But I have had years of experience finding enough to eat when eating out. I am polite, I ask what they can do and make suggestions, and most times it all works out. On this cruise, my primary thing was visiting the Hawaiian islands without changing my hotel room. I had such a great time that I am seriously thinking about booking another cruise for my birthday later this year. Remember, if you have special dietary needs, be prepared to provide some of them yourself and help the staff come up with options to your liking. And then relax. The ultimate outcome of your vacation is your perception of it. Expect the best, plan for the worst, and I'm willing to bet you will find some very happy middle ground.