Arguments are either about differences in opinion or one side trying to correct the ignorance of another party (aka educate). You can't have an "opinion" about facts. Facts are simply facts and if you disagree with them you are simply ignorant of them.
So to have an argument (at least the good kind) here you would have to either (a) make the case that one of my "We know" statements is wrong or (b) make the case that there is some moral ambiguity given (a). If (a) holds then that means the US attacked a more-or-less random country (or worse, a specific country for reasons which we have to hide). I think one would have a rather large burden trying to prove that to be morally ambiguous.
So to have an argument (at least the good kind) here you would have to either (a) make the case that one of my "We know" statements is wrong or (b) make the case that there is some moral ambiguity given (a). If (a) holds then that means the US attacked a more-or-less random country (or worse, a specific country for reasons which we have to hide). I think one would have a rather large burden trying to prove that to be morally ambiguous.