1) I suppose it depends on who you ask, but if you're wanting concrete proof, no, you won't find any. If religion could be proven we wouldn't have the debates we do about it. The belief in God is largely based on faith- you believe it is there even though you CAN'T see it or prove it. Many people have a problem with this system, as you might guess. Some people don't. It's my personal belief that neither is wrong and people are entitled to believe whatever they want to believe, as long as they extend the same courtesy to others.

Personally, I don't have a problem with faith. I do believe in God, but that's the result of my own personal beliefs. My experiences have led me to believe in God, but frankly I don't care whether or not someone else does, so long as they let me and mine alone and I'll do the same to them.

2) I think it's very dangerous to say "why do _____ people" do anything, especially for religion. Religion covers a very, very broad spectrum; people within the same religion tend to think and feel and even believe differently. To paint every single person with such a broad brushstroke as "religious people" and attribute one behavior to ALL of them is a huge fallacy. Not ALL religious people think black and white about religious vs. non-religious folks. Heck, a billion people can't even agree on what one book says.

I'm not making a very good case for religion, but then again, it's not my job to convince someone that they should believe for or against God. I think people should make up their own minds. I think that, no matter what, religion is a complicated topic and there are not absolutes. If you're someone who needs absolutes, then religion is probably not going to work well for you, because it does take faith, assuming you're talking about Christianity. Some Eastern-based religions are not quite so faith-based, and also have great principles on life. I'm Christian, if you want to pick my closest belief system, but I find a lot of value in Buddhist teachings, and recommend looking into them.