in the comments from Colo. about the radiant heat from the hydrogen combustion (implicitly: accelerating the burning of the oxidizer-bereft 'thermite' coating.)
But, agree that -- in the spirit of the pseudo-science of adversarial law? -- they're going for an either/or digital-think "Win!". Fie on academicians, seduced by such stuff..

Further, since there is no hypothesis [either] for the etiology (process-in-detail) via which the internal hydrogen cells + ambient air got ignited, only presumably.. via those "low-Joule" electrostatic sparks
-- it might just as well have been because of a cigarette-pack-size infernal device du jour. As in one of the movie versions.

So then: WTF killed the Hindenburg?
(Perhaps Ctulhu was aggravated by Herr Hitler's massive Nasty-god hubris, and decided to give him a sample of a er, Real-god nasty hubris?) Could. be.