Why did Israel unilaterally withdrew its military forces from Gaza and dismantled its settlements in 2005? It gave them what they wanted, and look what it got in return. Murderous terrorism.
I'm having trouble understanding the notion of "permanent military occupation of Gaza before 2005". Just out of interest, who occupied Gaza before 1967? And who before 1948? And who before 1920?
It's very doubtful the US will bomb Egypt over that, it didn't even bomb Egypt when it was directly involved in wars with Israel. Currently the Egyptians are in violations of the peace agreements with Israel over stationing military forces in Sinai, yet no bombs are falling.
Generally I think they targeted the US because of Islamist Ideology.
Islamism links conquest and imperialism to a proof of the religious validity of Islam.
Once the West has begun its control over Arab countries the idea in the 1920s has emerged where the reason why Islam lost its prominence is because they lost the "true" islam. Therefore the solution is to return to medieval Islam, similarly to fascism nostalgia to the Roman/German empires.
In that context, even the fact that the United States exists as a cultural force and influences arab teens to wear jeans is a major threat. Don't be naive that it is all over Palestine, Islamism started prior to the existence of Israel.