GTE, I do agree, not least because it is the accident investigator's duty under the Chicago Convention NOT to apportion blame.
On the other hand, whether the Authority failed to carry out a proper risk assessment before authorising an airshow with low vintage jet aerobatics over a major road with standing traffic will be a matter for civil claimants to establish on the balance of probability.
With so many people dead, I don't think the CAA can just shrug it off and promise to be more careful in future. There is clear precedent (
https://en.wikipedia.org/wiki/Abbeystead_disaster, for instance) for substantial damages to be paid even when an assessable risk is only identified with hindsight.