Well let me put this in perspective: During the Clinton era we bombed and put sanctions on Iraq that killed half a million Iraqi children, we force our sick and vile culture on the Islamic world, we prop up dictators and oligarchs who oppress them and steal and squander their wealth, we give the Israelis the weapons to crush the Palestinian people, we try to spread feminism in the Islamic world, we put soldiers, especially women soldiers on sacred Muslim soil near their holy sites, which Muslims saw as an act of defilment of America sending their temple prostitutes, etc.
After all of this don't you think terrorism would occur?
And no I'm not defending the 9/11 attacks. The terrorists were evil.