The simple fact is that some standards designed for men might be a totally inappropriate way to define if a woman is fit for the job.
To take an isolated example- the US army often has a bit of an obsession with straight bench-press style lifting. You don't actually need to bench-press to fight in combat but there is a vague correlation between that and a person's broader fitness (in a lot of people's opinions, not a very good one, but let's run with it). But that's going to give you the totally wrong result if you use the same benchmark for men and women, because the amount a woman would need to bench press to show she is broadly fit by that correlation is a lot less than a man would need to be able to do. So by applying the same standard, you are actually discriminating against women that could do the job well.
Now, if this was a weightlifting job (if you can imagine such a thing), then the standards would have to be the same as that is literally what the job is. Likewise, if the women here are failing on, say, marksmanship (and let's remember, their reasons for failing are not being made clear here), then that's a standard that should be identical and that's a good reason to fail them.
But broadly speaking, you cannot simplify the world into treating men and women in the exact same way and calling that equality. Equality is more nuanced than that- sometimes it involves adjustments to get a fair result.