A few people have pointed out that cognitive impairment might easily have led him to fly the Hunter that he had very few hours in like the Jet Provost that he had a lot in. The logic that follows is that if that basic error was the result of mild cognitive impairment then he's not to blame. Should we accept that view, if he is a highly experienced FJ pilot, instructor & ATPL pilot/BA Captain? Surely risk analysis - the risk of not having enough hours to be current enough to safely fly the display he wanted to fly - was entirely his own responsibility. That he had the right ticks in the right boxes was surely nowhere near enough, as demonstrated by the fact that he crashed the way he did, but more than that, he should have _known_ that the risk factors identified here were all holes in a Swiss Cheese that were lining up, waiting for him to have a fuzzy moment & fly a loop in a Jet Provost rather than the Hunter he was actually sitting in... in that interpretation, mild cognitive impairment isn't a defence, it's the mechanism by which his failure to manage his own personal risk factors, through gathering all the right box ticks without any of the reassuring current experience they are meant to warrant & represent, risk factors he had the experience to know about in advance, led to the 11 deaths.
Either those 11 deaths are just one of those terrible downsides of airshows and aerobatics 'being a thing', and we all just have to accept that one day the Red Arrows _WILL_ plunge into a primary school after a Ramstein style mid-air catastrophe, because that's the price of us having air displays over places where people live on & travel over the ground OR this happened because somebody [possibly multiple people] were negligent & failed to do their job of ensuring that this did not happen and/or ensuring that if it did happen, due to the hypothetical impossibility of preventing it, nobody was going to be underneath it when it did.
If Andy Hill had parked himself & his Hunter 6 foot under an empty field, I suspect that this would be a long forgotten incident, but he didn't & it isn't. However, I also can't shake the thought that if it hadn't been Mr Hill & his Hunter, we would at some point have been having a similar discussion about a bird strike afflicted Vulcan hitting a Tesco Extra or a formation of mid-air colliding warbirds at Duxford wiping out a couple of coach parties stuck in traffic on the M11...