I agree we have, as any nation does, a right to self-defense. I think that right to self defense does not extend to immoral behavior. As long as we agree on the torture bit, and that our administration is unethical in attempting to do so, or condoning it when others do it, we can let that bit alone.
That said, Iraq has/had nothing to do with fighting terror. We aren't "fighting terror" by being there, we are helping it.
I am not one of the "oil conspiracy" crowd. I am of the "Iraq was a mistake compounded by incompetence" crowd.
You say that Iraq is a good "platform" for fighting those who despise us. Here is a question: If we end up creating more people who despise us by using this platform, are we not harming our cause of self-defense?