Let me have my little rant here

I was doing really well. Yeah, I managed to travel all the way down from Vault City to many cities in the south. Shoveled a lot of shit, made a few quest from the wiki, helped out some newbies, collected stuff. I even had a nice Desert Eagle with some ammo and a lether jacket. Just made my little visit at the merchant in Junktown and wanted to head south to the Hub. So to put it simple; I had a lot of fun with the ~3 hours I spent and I was just about to go happily sleeping after that.
But then:
Random encounter with a police patrol, scorpions and some brahmins.
Everything's killing each other, but the police patrol has won the battle, of course. Yay Brahmin hides I thought!
While collecting the second hide, which was laying close to a police guy, he simply gave me a smg burst in my head... cool!
A bluesuit joined the scene. While trying to loot my body they did the same to him.
And to quote his last words: "...this sucks!..."
I know, the wasteland is harsh. But this was simply and purely unrealistic.
Or can someone explain me why those cops act like fucking raiders?
And how am I supposed to know, that they get pissed off by looting the brahmins in the first place?