I've read, many times, that HAL is reimbursed a percentage of the "free" cruise by CCL's casino division.
I know in my case I wouldn't have considered a Caribbean cruise if I hadn't been offered a "free" cruise. My mom enjoys them so we went. We purchased Club Orange to be able to select our cabin. We purchased a wine package. Mom went on 2 excursions and had a massage.. We ate in the specialty restaurants. This is all money HAL would not have had if not for the "free" cruise they offered. I'm pretty confident HAL has run the numbers and found that these cruise bring in enough revenue to justify offering them. Perhaps you have information to share with HAL that would help them see where this is a mistake on their part.