I'm really not sure how the fact that BP and Transocean are to blame for the disaster (a fact nobody, including BP, would dispute) means we can't criticise the

I'm really not sure how the fact that BP and Transocean are to blame for the disaster (a fact nobody, including BP, would dispute) means we can't criticise the screw-ups in the US government's response. In your police/murderer analogy, of course the murderer bears the sole responsibility for the actual murder, but if there's a serial killer on the loose and you find that the entire homicide squad is focused on a four-week intradepartmental tiddlywinks tournament then you're allowed to be pissed off at the police too.