Personally, I'm a fan of shooters because I like the movement. Humans tend to be aggressive and competitive by nature, and hunting something down in a video game is therapeutic. I like the physics, seeing how different game engines perform, and I like the sound. Mostly I like the pacing, which in my experience has been faster than other genres. For the most part, I've found that shooters have more intriguing story lines, which is another draw for me (in this case I'm thinking more along the "action" aspect, and I'm not just thinking of FPS games - For the sake of argument, let's include TPS games too). That, and I'm just very good at them for some reason, so I tend to play them more by default because, hey, everybody likes to win. To be fair, I play a large array of games, but the first game I ever played was a shooter and I just kinda stuck with them.
I have shot actual guns. Several of them: Both a 12-gauge and 20-gauge shotgun, a .22 rifle, a .40 S&W, and a .45/.22. Holding an actual gun didn't change my outlook on games at all because, thankfully, there's a huge difference between me tearing shit up on my television screen and me shooting clay pigeons IRL. Yes, I've held multiple weapons that can kill people. But that doesn't make the gun I look at on-screen any more likely to shoot the person standing next to me. Owning a hunting knife doesn't make my combat knife in Black Ops any more likely to stab me in the gut.
I can definitely understand the reasoning here, though. We fear death, and actually holding in our hands something real that can very easily destroy a person certainly has the potential to change one's outlook. I suppose I just look at it a little differently...