The main reason is that terrorists hate the US because of morons like Trump.
So what were the terrorists' big beef with the US prior to 9/11 then? They were still peeved about the 2000 election results and yearned for the "good ol days" of Bill Clinton? lol
We've had our noses in their politics and wars since the 1950's.
We've meddled in alot of other countries' and regions' affairs over the last 50 years or so too and committed plenty of atrocities far worse than the war in Iraq, but for some reason it's only the ones that are dominated by radical Islamists that seem to have it out for not just us, but the entire western world in general.
Just as an example, during WWII we nuked and napalmed the hell out of Japan, killing hundreds of thousands of innocent civilians in the process, most of whom were women and children. During the Cold War / Vietnam War era, again we slaughtered countless Vietnamese simply because we feared the spread of Communism in the region.
Yet somehow today we are buddy buddy with Japan and Vietnam and do business with both like we've been BFFs since day 1, and neither population is trying to wage a neverending jihad against us despite having every right to do so considering what we've done to them in the past. I wonder why that is...
Might have something to do with us immediately building diplomatic relations and staying out of their politics where as we've been bombing the Middle East and meddling with their politics for decades.
We bombed Japan 70 years ago and have worked hard to atone for that since. We've been bombing the Middle East for decades straight and we apologize by bombing them some more.
Tell me, if a country killed your friends and family, destroyed your way of life, changed your political system continuiously, removed your army, installed a new one, removed it again, armed and funded your enemies, stole your resources, burned your farms but saved your drug fields, etc....for decades. Would you turn to that country and say thank you or fuck you?