Both.

It is fair to do a detailed investigation of the fires as the regulator is fairly unfamiliar with high speed electric vehicle crashes and any resulting fires and so from the regulators perspective it is wise to be cautious, because if they get it wrong they could suffer considerable political fallout.

It is also fair for Tesla to feel that it is getting unfairly overscrutinised by the regulator, because it probably is compared to a manufacturer selling a similar number of petrol cars.