The honourable role of the muck-raker

Brian Deer's excoriating exposes of the shenanigans behind the dodgy Lancet paper by Andrew Wakefield )and others has been reprised and expanded here and elsewhere in the BMJ.
The first two lengthy pieces in the three-part series the BMJ published attracted huge attention in the press, and numerous comments from readers. The third virtually no attention and just one comment.
The responses to Deer have been critical of Andrew Wakefield, who has been (rightly) struck off by the General Medical Council, and who no longer has any scientific credibility, whatever the support he attracts from desparate parents of autistic children and others. Others, like Ben Goldacre have been hugely critical of what they see as the excesses of the media in their original reporting of the Lancet study, and in their consequent coverage of the issue.
No one has taken up the points made by Deer in his third article about the behaviour of the Lancet's editor Richard Horton who does not emerge well out of Deer's reports. As well as the misjudgment of publishing the paper, adding the cachet of the journal to a highly speculative small case series, Deer reports that the Lancet was involved in a cursory investigation into the quality of the paper, when Deer raised serious issues about the trial's conduct, which the Lancet then used to defend its decision to publish.
One of the strengths of Horton's editorship has been a continuation of the Lancet's history of mischief making in the public interest; stirring things up, for example, by publishing controversial studies about the number killed after the 2003 invasion of Iraq. (paywall).
With the MMR story Horton's nose for a controversial story was on target, but his judgment was not. It has taken the multi-million pound costs of a GMC enquiry for the truth about Wakefield to come out.
Deer does emerge from his own account as someone with a healthy ego, not slow at putting himself at the centre of the story. But his kind of muck-raking hack who gets hold of the documents and tracks down often reluctant interviewees is unlikely to be a shrinking violet, nor a clubbable member of the medical elite. The time and effort Deer has put into exposing the MMR paper scandal justifies his high opinion of himself, even if it does lead him to see medical professional collusion, even among fierce critics of Wakefield, where it did not exist.
What has so far been missing is an adequate explanation from Horton about his apparent role in allowing himself to become a party to a flimsy investigation, and undermining Deer's painstaking investigation.
Asking awkward questions, keeping on asking them long after everyone else has become bored of them, and following all trails of of inquiry should have been part of an inquiry carried out by medical academics as soon as serious concerns were raised about the Lancet paper. Instead it was left to a muck raking hack (and that's a compliment). Medical snobbery about Deer's work did delay the truth emerging. That is the tragedy.