I've been to Egypt three times (as well as having visited other Middle Eastern countries) and have never had a problem. I happen to really LIKE Egypt and the Egyptians.
The only Middle Eastern country I was ever a little apprehensive in was Israel.
PS You'll LOVE Crystal. What ship will you be on? If it's the Symphony, you must eat in the alternative dining restaurant PREGO. They have absolutely MEMORABLE wild mushroom soup.