Oooh...I like this take on events. And it is VERY difficult for siblings to change how they see each other as adults...especially if kids grow up close in age.

I don't know about anyone else, but every time I go home and spend a holiday weekend with the entire family as an adult...almost 90% of the time, all the siblings fall back into their teenage patterns. It's hard to break away from all those years of behavioral conditioning. And really, Sam and Dean are still pretty young, and have been under stress since they *were* teenagers. Four years apart, then they're thrust back into their old roles, AND had added stress piled on and on and on. It's no wonder they haven't matured much beyond the "I'm the big brother, I'm in charge" and the "You're just like Dad, but you know this life better than I do" mentalities. They haven't had TIME.

But both Uriel and Zachariah have been proven to lie, to manipulate the truth to get what they want. Did any other angel say that only an angel could kill another angel? (I don't remember). It could be a hole in continuity, or it could be a clever ply from the beginning. (Or it could be both, depending on which writer said it and which writer changed it.)