Ah but...
You can't both dilute it with atmosphere AND have less oxidants
(I know the Challenger situation had both LH2 and LOX, but reading the report, the bulk of the hydrogen exploded because it mingled with the atmosphere, and didn't need the LOX.)
Liquid hydrogen has a number of problems. It is highly diffusive, cryogenic (and so many materials become brittle on exposure to it), and it burns with a nearly invisible flame in daylight which is also intensely hot.
In comparison, gasoline is safe.