Vietnam was over 30 years ago. What happened there has little bearing on war today.

Afghanistan is a different situation, and one in which civilian casualties have been extremely low in battles conducted by western troops. Have there been civilians killed? Sure, but not in the thousands as you have claimed. And there is no reason to believe that war with Iraq will follow that pattern. A better choice would be to look at the Gulf War, which had very few civilian deaths.

As for the final comment, look up Neville Chamberlain.