Why is it dumb, and why does it matter? Please explain.
Because people act on their beliefs - it's often called faith - and it doesn't have to be scientifically proven to matter. One obvious example is radical Islam. Is there any proof of what they believe? NO! Does it matter that they believe their holy purpose on earth is to kill Jews and Christians and other less radical Muslims? HELL YES, IT MATTERS because people act on their beliefs! You really didn't know this?!!!