In summary, the US bombed a village in a foreign country, with which we are, at least technically, an ally. In doing so, we could not know how many people we would kill, or whether we would kill "insurgents" or civilians. We claimed we only killed a few civilians while killing scores of insurgents. The UN and Afghan government investigated, and concluded that we killed dozens of women and children. We only changed our story when video evidence surfaced which rebutted our lies.
This type of action doesn't help defeat terrorism. It merely serves to give terrorists a rallying point to show that the US is killing women and children in their countries, and lying about it until they're caught. Sadly, I can't argue with them on that.
If the survivors in that village didn't hate the US before, you can bet they do now. By becoming involved in nation building and foreign wars, we undermine our own security, rather than enhance it. We killed millions of civilians in Vietnam, the first Gulf War, the decade of bombing and sanctions that followed, Afghanistan, and Iraq.
Before anyone says that my approach would allow the terrorists to "win", consider how we should define our own success. Do the terrorists hate us less? No. Are there fewer terrorists? No. Are there more people who hate America? Yes. None of those sound like victories to me, yet our policy is leading us directly to those results.
The terrorists don't hate us because we're free and prosperous. They hate us because we're meddling in their countries, killing their people, and propping up unpopular totalitarian regimes which use our weapons to kill their people.
We've been doing so long before 9/11 ever occurred. I'm not saying that 9/11 was warranted. Clearly it wasn't. But we likely could have avoided it with a different foreign policy. Our current policy makes it more, rather than less likely, that something like it will happen again.