I believe Colin has, already, taken responsibility. If you have not done so, I recommend you read his book - both editions, if you can. The notion that he should take further blame or responsibility is, in my view, obscene. In my own comments about him, I only suggest that he should be seen as responsible for what he did and did not do, and no more, and whatever consequences he may suffer for it have been suffered in the terrible loss of his sons, for which he deserves our unending sympathy and condolences.
I think it is OK to criticise Colin. He won't like it, and may be offended and protest, and I don't blame him, but it is what it is and what happened, happened. To comment on this case from the side-lines leads, inescapably, to the expression of judgement of the individuals caught up in it. We all have shortcomings.