Why would anybody do this? Is there a rhyme or a reason to the way some people behave?
You take a leap of faith and send in your troops to liberate a country from a tyrant (even though the tyrant probably was not going to harm you or your people, making this deed all the more altruistic). You sacrifice 5000 of your troops in this noble endeavor.
You take a beating in the court of public opinion in your own country because you sacrificed 5000 precious lives to liberate a nation of 25 million from the throes of an evil, genocidal dictator.
Clearly, having been such a savior, you would expect a little gratitude. You would expect, perhaps humble words of thanks. Tears of affection, perhaps. But shoes? Would you expect shoes to be thrown at you when you were so instrumental to the state of freedom Iraq is in?
What was the attacker thinking? Every Iraqi is obviously happy now, that he has been liberated from the evil dictator. How can anyone bear animosity towards such a benevolent benefactor? Human beings are such ingrates. Dear reader, let this be a lesson to you: the next time you see a dictator, don't liberate his subjects. They will throw shoes at you later.
Or, you could refrain from killing 4% of the subjects while liberating them. That could help.