War a mistake?

Will someone explain to me why it took rtwelve years and 4;491 american lives and countless number of Iraqis to die for our Presidental hopefuls to realize that that the Irak war was a big mistake.In the first place it was based on a falsehoo that Iraq had weapons of mast destruction when nome was ever found.And now i;s agreed that it was a false war and should not have been.Well if you are dead because of the truth or because of a lie you are still dead right or wrong. And now after all these years and so many deaths they say the Iraq war was a MISTAKE. Heaven help us all.