And This Is Fun...How?

Hello, this is Ms. A.F.!
     As of one month ago, my brothers are obsessed with Airsoft guns. For those of you who (like me a few weeks ago) don't know what Airsoft guns are, let me clue you in. They're alot like b-b guns, but instead of shooting little metal balls, they shoot little plastic balls. Yep. They come in all shapes, sizes, and prices, from a little pistol to a huge mega-monster machine gun that could kill a small mammal. It's pretty intense, apparently.
     Now, when I say my brothers are obsessed, I really mean obsessed. They sleep, breath, talk, eat and think Airsoft at all times. They talk about which gun they're saving up for, how they want new attachments for the guns they have now, what color their b-bs are, how heavy the front end of the hand gun is compared to how hard to cock the shotgun is, FPS (feet-per-second, I believe) and accuracy, and how totally awesome guns are in general. It really never ends. They even dream about Airsoft guns. My second oldest brother spent hours (and hours) on Youtube last week watching video reviews on different guns with different gadgets attached and such.
     The other day, I made the sorry mistake of going to a local sporting goods store with my two brothers and my dad to look for a new Airsoft gun. Let me be clear: I wanted to go to the fabric/crafts store, to which they were going to take me after they were done. I did get to go to my store, but only after watching my male relatives for almost two hours, whilst they decided whether they wanted more or less FPS in a machine gun.
After much deliberation, they finally decided to try a different store, where they finally found the gun for them. It was quite touching.
Now they run around outside shooting each other. ALL. THE. TIME.
     What is it about guns and weapons that makes guy's hearts go pitter-pat? Why in the world is it fun to shoot each other with small plastic b-bs going 350 FPS? Why, why, why? It is far beyond my capacity to understand. I feel the same way about paintball.

Confused,
Miss Artsy Fartsy