They flocked in once the place started to become prosperous. The same thing happened in Algeria, after the French brought modernism and better agriculture, etc. (all the things Islam disparaged).
Most of today’s Gaza residents are Egyptians who were trying to flee back to Egypt in 1948 and were caught, and stuck, in the Gaza when Egypt wouldn’t let them back in.
Correct. Yasser Arafat himself was Egyptian-born.