I would be careful to differentiate between "cold," which is an emotional evaluation, and "realistic," which is an objective evaluation. There is no way to gauge someone's sympathy without meeting them eye-to-eye, so it is best to give everyone the benefit of the doubt in that regard.
Well, let's be careful. I would like to believe everything the OP said, and would like to share in the outrage for the alleged rudeness, but I've been burned many times over my almost-25 years online by people reporting something that was so far distorted from the truth as to be close to a lie. I highly doubt that is the case here, but what years online has taught me is to allow for there to be "another side of the story" whenever we read only one side of the story.
Rather, I would interpret his intent as a helpful warning for all of us to never expect anything for which we don't have an explicit guarantee in writing. WDW is a wonderful place, and problems are few and far between, but they do happen, and sometimes we just aren't going to get what we hoped for. The message I get out of this is to be ready to adjust to things like this, and not allow them to significantly affect my enjoyment of my vacation.
For the OP, I'm sorry you had such a troubling experience, and hope you have a great time at WDW otherwise.