I imagine your "logic" was used before we entered WWII also. Seems to me the guys name was Chamberlin. And he was clueless to the threat.
According to the Qur'an: "Muhammad is the Apostle of Allah. Those who follow him are merciful to one another, but ruthless to unbelievers" Sura 48:29.
"Kill the Mushrikun (unbelievers) wherever you find them, and capture them and besiege them, and lie in wait for them in each and every ambush..." Sura 9:5.
Ok, take a deep breath and try to follow: Chamberland was the British Prime Minister, and had nothing to do with the United States. The United States had nothing to do with the transfer of the Sudetenland to Germany, we were not a party to that agreement.
US Entry into WWII was caused by the fact that: