The last time I visited Dahab (a very simple yet beautiful place in Sinai, not sure if you know it or not), I saw an Arab man, from his accent it was clear he is not an Egyptian, maybe he is a Saudi or Kuwaiti, he was having a discussion with the Hotel's reception about being charged more just because he is not an Egyptian. This is just something stupid they do to get more money. I am sorry that you had to pay more for the same service.
I didn't mind the overcharging too much when it was obvious. Like it was funny to me and the taxi driver that he was charging too much, and we had a laugh about it. Coming from the USA, the flight cost far dominated any expenses from when I was in Egypt. The one time it did feel bad was when the tour guide I hired, who seemed to be on my side, let me be overcharged by someone he had a prior arrangement with. But alas he was so knowledgable.
I realize all this is only a small part of Egypt and it's not fair to judge a whole country by a few bad apples.
One of my new Egyptian friends wanted me to try so many types of food that he sent me home with two extra bags of stuff. That's excessive hospitality :)