It's your knowledge of history and understanding of where radicalisation comes from that's off.
Let's go back to the first century of Islam and not just the 19 fucking 70's. What western conquest created the Kharijites? - look them up.
Ah the old "you know the US funded these groups in Afghan and Pakistan" argument that people use to try and make them look clever and like they know something the rest of the world doesn't, when everybody does know about it already.
Do you not think the west supporting these groups to defend themselves from invading Solviet forces should have been rewarded by the murder of US citizens?
Western intervention in the Middle East has been far from perfect, but to blame that on the reason why Muslims carry out these atrocities is garbage. They do it in Africa, they do it in Baghdad, in Istanbul, in Libya, in India. They say themselves that Iraq and Afghanistan isn't their main reason for doing it, it's because they hate western values and the values of Christians, Atheists, Hindus, Jews and other Muslims.