Why is it people have a single incident, and then love to act as if it's a Worldwide policy?

Elevators to the different floors are supposed to be for hotel staff and guests only.

There is nothing that qualifies a delivery person to be a delivery person. Many a crime have been committed by someone claiming to be something (like a delivery person). Once they are on the elevators, they can access any place in the hotel wthout restriction.

If this unrestricted access at one hotel puts a bad taste in your mouth for all of Hilton, so be it. You're going to find the same restrictions at many other hotels around the world.

And it has nothing to do with hotel revenue. They aren't prohibiting you from bringing food in...they're just prohibiting you from getting it delivered to the room. Go to the lobby and enjoy a beer with your delivery person while you eat the food ...they don't care.