I don't think it has anything to do with valuing human life or not.

I'm sure we both agree the US values human life, but the government is more than willing to accept the death of a 16 year old American citizen when trying to target his father during a drone strike.

I'm more surprised that they would reveal their hand so suddenly. Maybe I watch too many movies, but I would think if you have exposed the entire network, then doing counter-espionage would be the smarter tactic.