This is based on a failing of mainstream science, IMHO. H2 has been observed in space where it's hot enough to be detected. How much there is in space is not known, since it can't be measured with current tech where it's cold. In the formula that leads to the notion of expansion of the universe, astrophysicists take one atom per cubic centimeter of H1 into account. If they didn't they would think the universe was expanding even more dramatically. They don't know how much H2 is out there and therefore leave it out of the formula, although it's thought to be at the very least five molecules per cubic centimeter, which is enough to kill the notion of an expanding universe. To me, that's not science.
This has been known for quite some time and was first published in Nature in the late 1990s. Mainstream science is also claiming that the galaxies beyond the Hubble horizon are exceeding lightspeed as they move away from us. If that were the case, why wouldn't the nearby ones be doing it, too? Expansion is supposed to be somewhat uniform in all directions, where in an explosion all participating particles are considered to be moving away from their cohorts at a virtually equal rate (except for any slight effect of things like wind).
With a missing variable, they don’t know yet constantly repeat claims that should be considered wrong according to the data available.