I think Parkrun's decision is probably a good thing in terms of getting to the crux of the issue.
Initially, the two main arguments available to them in saying that males are female were (1) sex doesn't matter in running and (2) competition doesn't matter.
If they had gone with the first option and deleted their 'gender' categories, only women would have been disadvantaged and men wouldn't have cared as their times wouldn't have been affected. (Obviously, this option would have been a harder sell anyway, given the general direction professional sport is moving in).
But by doubling down on their argument that competition and stats don't matter at all (and essentially implying that grassroots and amateur sport doesn't matter) they have managed to shit on everyone equally and undermine much of the appeal of Parkrun for many of its supporters.
If they end up reinstating the competitive element, they will have to concede that it's unfair to women to not have their own category based on biology, since it can't be the case that only men should get the competitive element back but not women.