Why did they attack us again?

An exclusive interview from WTOP with a former Al Qaeda insider says that Osama Bin Laden had no idea that the US would retaliate the way that they did. Quote:

"What happened after the 11th of September was beyond their imagination, " says Benotman, who adds that al-Qaida thought the U.S. was a "paper tiger."

He continued...

Benotman attributes al-Qaida's overconfident attitude to the United States' response to al-Qaida attacks on its in embassies in Nairobi, Kenya and Dar es Salaam, Tanzania in 1998.

Zawahiri, according to Benotman, expected only a missile attack.

"When they attacked the embassies in East Africa, they estimated the U.S. launched 75 cruise missiles and eight people got killed. So they said this time, maybe they will launch 200 and they laughed about this."

This revelation flies in the face of the common perception that Western globalization or US foreign policy is why we were attacked on 9/11, or that diplomacy will resolve our issue with Islamic extremeism.  In fact, non-engagement escalate attacks far beyond what would otherwise be. I'm not saying that the global economic environment or American intervention doesn't play a role.  But given this, it's not a good argument for not confronting treats as they arise.