[It's not exactly a surprising reaction, considering what Scott just confessed to; Dean doesn't expect he's very popular amongst the supernatural crowd. Jesse had proven that much, too.

But then again...

So Dean doesn't protest, but he does let Scott run himself out a little before he tries to talk over him.]

No.

I don't kill people.

I kill anything that preys on people. I kill things that kill people. And I do what I have to do in order to keep as many people as I can safe. But sure, you can go that way if you want.