Hindenberg didn't crash due to a fire in the hydrogen. Hindenberg crashed due to a fire in the fabric covering, which was itself caused by a combination of poor electrical bonding or an access panel and the choice of red-oxide primer and powdered aluminium top coat in the nitro-cellulose dopes used on the fabric.
Sure, the hydrogen burned in the crash, but burning hydrogen didn't hurt anyone; the few of the casualties who got burned were actually caught in the fires from the ruptured engine fuel tanks.
You can see this in the film of the accident - the hydrogen flames have a distinctive colour and are all ABOVE the structure, whilst liquid fuel flames are much yellower, and fall down from the structure. You can also see moulten iron being spat from the burning fabric as the aluminium dust, iron oxide powder and nitrocellulose dope combined to create a classical thermite reaction.
The hydrogen burned in the crash, but it didn't cause it any more than the fireball of burning fuel that accompanies most tent-pegged aircraft was necessarily the cause of the tent-pegging.
For reference - the RAF operated a number of barrage balloons as part of the paratroop training process from the 1940s up until (IIRC) 1995. I vaguely recal they were based at RAF Hullavingdon (then a satellite field for RAF Lynham). These balloons were always hydrogen-filled because helium (a) gave less lift and payload, and (b) was simply unaffordable. They simply recognised the risks of using hydrogen and developed operating procedures to mitigate them. I don't *think* they ever had a hydrogen accident, but I could be wrong on that.
PDR