People die because of lies all the time, those they believe and those they don't. Look how many people died in Iraq over the lie that Saddam Hussein was connected to 9/11.
Of course, if you know your audience, choose an example that suits them. There are tons of examples.
How many people died for the lie that the Aryan race was superior to everyone else?
How many people died for the lie (and believed it, too) that communism was the salvation of the poor?
How many people died in this country for the belief that blacks were inferior to whites during the Civil War?
How many people died for their pagan gods before the common era? And after?
How many Japanese died for the lie that their emperor was a god on earth?
How many people died for the lie that prayer was efficacious?
I trust I've made my point. It's not difficult to die for a lie. And it's a shame, but dying for a thing doesn't make it true.
Of course, if you want to be mean about it, one could turn the question around in another way: Many people have killed for their faith, too. Does that make it true?
That's not a proof. We are 60% through the list and I'm still waiting for a good one.