Why put BEER in chili?

 
The other day I was bored and ended up watching the first few minutes of this Food Network (like) show, which showcases a certain food and the best places in the country that has it. I think I may have seen this series before, when they did a show on Steak and another on hamburgers.
 
This one concerned chili, and in the introduction to the show, went to Texas. I turned it off when some guy told the camera, "This is the secret ingredient..." and pours a bottle of beer into the soup. I rolled my eyes and changed the channel.
 
I have heard of this before, but why in the hell would someone cook with beer or put beer into something like chili. Don't get me wrong, I love beer.  But to me, putting beer into food just ruins it, and I would kick someone's butt if they put that in my chili, because the chili would not be worth eating and be spoiled.
 
I think people who do this are drunken men who thinks for some reason that this would be a cool thing to do for some reason. It's a male, machismo thing. Dunno.
 
So, why put beer in chili (or anything besides my mouth and my liver?)