That was a position used to justify action, rally supporters, and which was quite overtly an instrumental (rather than terminal) goal in their grand strategy --- which was -- like that of Daesh -- to achieve a pan-Islamic caliphate.

(It's worth noting that al-Qaeda was formed several years before the Iraqi invasion of Kuwait that prompted the creation of those bases, and adopted the position of opposing the bases after the Saudi government turned down bin Laden's offer for al-Qaeda fighters to defend the Kingdom against Iraq in favor of accepting aid from the United States. And both al-Qaeda's long-term goals and their anti-Western rhetoric existed before those bases.)

> Not saying terrorism is a legitimate response, but it's much more explainable than "they hates us for our freedoms."

Sure, but not for the reasons you propose: al-Qaeda's opposition to the West is because their strategy for achieving dominion in the Islamic world is the time-tested strategy of totalitarians everywhere -- sell the target population on the threat of an external enemy, and use that to sell the idea that the totalitarian leaders and their proposed system of rulership are necessary to combat that external threat. Its not a response to anything the West does, although anything that the West does that creates (or can be fuel for propaganda to create) widespread grievances (legitimate or not) in the populations in which al-Qaeda seeks to establish its caliphate will be leveraged. Daesh is much the same in this respect.