A century from now, when the competitive flux among world cultures will doubtless be as intense as today, your stern view of Iran may well have been proved correct. The failure of the West to act decisively and to intervene in Iran's nuclear armament may look timid and foolish. If nuclear weapons manufactured in Iran end up in the hands of jihadists and are successfully deployed in our capital cities, the West will look as if it committed suicide and deserved to fall.
But politics is not science.
It is impossible to predict with perfect accuracy the real-life results of any course of action. A thousand unanticipated factors may cause idealistic plans to go horribly awry. In the case of Iran, short of a massive land invasion or the outright assassination of its leaders (currently forbidden by civilized nations), it would be virtually impossible to surgically remove Iran's regime without visiting death and destruction on untold numbers of innocent Iranian civilians. Do their lives mean nothing to you? By what ethical reasoning have you determined that the American way of life, which I too love, is or should be paramount on Earth, at the expense of all others?