ByB writes : He's obviously someone with an anti-American outlook and now takes the opportunity to vent it. Fuck him.

I think the writer of the article expresses strong misgivings about America's foreign policies, but that does not mean he is anti-American - no doubt he has close ties to many Americans.
Just because someone expresses opinions regarding the international and historical situation within which these acts occurred, in order to make some sense of the current position it does not mean that some justification of the crimes has been attempted. Rather than offering some treacle about a 'faceless coward' as if these attacks occurred within some vacuum, one should try to forge positive steps (i.e. not military action) which can be taken to alleviate the hopeless disparities at present.
I don't think I live in the same world in which the perpetrator's supportors live, but I can *try to understand what they *might feel like - that's not wrong, Bob.