Another terrorist says that he attacked the US because the US keeps attacking Muslim countries. Why do we ignore this?

Asked by SquirrelEStuff (10007) September 24th, 2016 from iPhone

The official complaint from the most recent terror attacks states some writings in the notebook of the terrorist.
Just as with every other terrorist that is captured, it states that he attacked us because we are in the Middle East attacking them.
This is a commonality amongst almost all terrorists captured, including the underwear bomber, shoe bomber, Boston bomber, Orlando shooter, and Osama Bin Laden.
How can an entire country ignore these facts and continue to assume that these attacks are strictly because we are “free and non-Muslim?”
This is kind of a big oversight, no?

Here is the formal complaint, and here is the specific quote, “You [USA Government] continue your [unintelligible] slaught[er]” against the mujahideen, “be it Afghanistan, Iraq, Sham [Syria], Palestine … ”

It is also worth noting that the stabbing at the mall in Minnesota was done by a Somali. The US has been bombing Somalia for quite a while now, with the most recent reported airstrike being two weeks ago.
Of course it doesn’t justify what he did, but I wonder if he lost some family in the airstrike.