The bottom line is that without giving birth, the species stops forever. Women are the ones who give birth.
Men are needed for a few minutes to initiate this necessity, but that’s it. So what else are they good for?
Well the best they can do to be chosen to fulfill their part is to offer a healthy albeit potentially brief contribution, and/or perhaps even assist in the longer term by compensating for the resources that a woman has to sacrifice in order to give birth and bring up a child. The better they can do those 2 things, the more they’ll be chosen to be involved in the whole thing, and if they don’t contribute enough in either or both of those things, they’re literally worthless.
All women are necessary, though given enough women, some not being necessary is allowable.
But most men are not necessary - a much smaller proportion of them are needed to fulfill a potentially minimal contribution, though at least it’s not as small as it could be given that assistance in child rearing has value. Human babies have evolved to be delivered prematurely to allow them more time to adjust to the ex utero world when they would otherwise be in utero.
It’s hard to be necessary, but it’s also hard to be constantly under pressure to prove yourself to those who are necessary, and it’s hard to fail in this regard and be worthless.
Which is privileged?