It's a very common mindset, to think that toughness will make you invulnerable.
Isn't that what Bush's 2004 campaign was all about, and the reason people voted for him? "9/11 changed everything, and I'm waging the War on Terror™, which means I'm tough!"
Also, I hate to slam some of my fellow Americans, but the "I'm so badass" attitude isn't just a stereotype (when you're talking about Bush voters, in particular).
It's also a mindset that makes terrorism a bigger problem than it is.
Right - I mean, the Iraq war was all about being "tough" and taking down Saddam. And look what happened: terrorism has INCREASED, in part because of the Iraq war.