> Defending yourself doesn't mean attacking ...
Here in the U.S. there's a common sports phrase, "The best defense is a good offense." This carries over into our military policies. For example, while other countries may benefit from our military presence, the reason we send our military into a situation is to protect the U.S.. There may be an immediate benefit of protection or it may be a long-play protection (e.g. "placate the nationals so we aren't contributing to the future pool of terrorists"), but ultimately we send our military in to protect ourselves and this is frequently a preemptive defense that can be seen as offensively attacking.
Again, I'm not condoning any terrorist attack, I'm just not buying your statement that "Defending yourself doesn't mean attacking..." I'm also not saying that preemptive offense is a moral correct policy; just that it is a common policy.