Am I completely off-base thinking that the OP has a point given that the delay out of IAH was minor? That means that the staffing for the flight more than a day out was guaranteed not to be able to turn on-time. In such a logistics intense business not being able to fix a pretty simple timing issue with greater than a days notice is fairly sad if you ask me. Beyond the OP's specific experience, to me it betrays a pretty stark lack of basic sophistication from an operations perspective. I highly doubt that the decision was a pro-active "this is the least worst outcome, delay the HNL flight 6 hours". I'm willing to be it was more "we have no ability to affect the outcome with only a full day's notice... I guess the HNL flight will just have to be dealyed 6 hours".
To me those are very different scenarios from an operational point of view. There are plenty of slim margin logistics intensive businesses that can do a lot better. Many of them unionized with their own esoteric work rules.