Bad At Class Royals?

Listen up, buttercup. This joke is saying Americans are bad at "class royals" (like homecoming king and queen) because they already "lost 2 towers." "Lost 2 towers" is a dark joke referencing the Twin Towers that were destroyed during the 9/11 attacks. It's like saying they've already had their big loss, so they can't handle another competition. You probably were picking your nose when they taught you about 9/11.