I don't think this case shows the callousness of the American pilots. It was determined already that the incident was a horrible case of "friendly fire" (I hate that term) and this new revelation with the exact conversation between the pilots changes nothing. Tape also shows the two pilots' realization of what had transpired, they certainly weren't joyed over it.
If anything it just reveals the ineptitude of the US Department of Defense. They should've just exposed the tape in the first place and they should have exerted some effort in applying some punitive action to the pilots. Letting them off the hook is downright disrespectful.
In other news:
Iran blames US for kidnap of embassy official in Baghdad
Oh what's that Iran?
You didn't think the Sunni's would your ass too?