This demonstrates well the insanity of religious people. As 12 Monkeys alluded to, the Christian religion has wreaked unbelievable havoc and disaster upon Native Americans, exploiting them, enslaving them, killing them, taking all of their land and possessions, it's really a rather long list of offenses, which one could certainly add to mine. Disease brought from Europe, such as the plague and smallpox, killed 100 MILLION Native Americans.
What did these Good True Christians think about this? They saw it as vindication from God that the New World was their Promised Land, their New Israel, their City Upon a Hill, and that God ordered this horrible holocaust in order to grant it to them. They would delight at the sight of a native village utterly wiped out by smallpox, or an entire tribe succumbing to the plague, and would nod and praise the Lord. They considered this a just fate and punishment for being savages who didn't believe in God. Hell, Andrew Jackson and others would send Native Americans blankets and clothing infected with smallpox with the direct purpose of wiping them all out. They gloried in the death and slaughter of their enemies, and praised Jesus the whole time.
THIS IS EVIL! How can people ever say that Christianity is a good thing? 100 million dead makes Hitler look like a saint (he was Catholic afterall). All of this happened precisely because of religion, and the people who did it thought that they had divine sanction to do this. It was their destiny.
As to their whole rant about a lack of God and religion being the reason for moral decay, it's all too common babble, and it's utter nonsense. Hitch said it best "Given only faith, mountains can be moved and millions of people who would never normally acquiesce to evil are brought to it straight away and with ease and with self righteousness." Religion is utter nonsense and causes so much unnecessary evil, yet people still think it wouldn't be possible to be good without it!
I've pointed out before that we never hear Richard Dawkins or Sam Harris saying anything wildly and utterly inappropriate in the wake of terrible tragedies such as the Newtown shootings or Hurricane Sandy. Without religion, there would probably be at least a 70% reduction in the amount of evil and corruption and racism and violence in the world.