I thought the Trojan Horse should not be in the same category as the other five. One that could compete with the Trojan Horse would be Winston Churchill's idea to fight in Gallipoli to end the first world war.
*Haters are just rude desperate cowards who are so miserable they feel the need to share that misery
How about Lee at Gettysburg? His officers were telling him to lure the Union Army off the high ground by feigning a march toward D.C., but nope, he insisted on charging the high ground. NOT GOOD STRATEGY! So he lost Gettysburg, and probably the war at that point.
I'm not as up on my American history but it seems they could've come up with 6 blunders of war and then done a show about the 6 worst mistakes in the entertainment industry. The minute I read your post I thought about Custard's last stand or the arrogance of Xerxes sending his men into battle through that narrow pass at the Battle of Thermopylae.
*Haters are just rude desperate cowards who are so miserable they feel the need to share that misery