The connection that isn't?

Ken Livingstone and Sir Ian Blair have both gone on record to say that in their opinion "nobody was to blame" for the death of Jean Charles de Menezes. Maybe so, maybe not, but when will we learn to accept that "responsibility" and "blame" are not the same thing? Clearly somebody (maybe more than one person) must have been responsible, in that their action - or inaction - led directly to the outcome, and perhaps if we could break this link between responsibility and blame, they might be prepared to come out into the open and 'fess up.