The army is under a lot of pressure to become more "inclusive". If the standards for female recruits were the same as they are for males, no women (with a few exceptions) would be able to join the marines, or any other corp. Despite the popular narrative, men and women are not equal when it comes to physical capacity. It doesn't mean that women can't join the army in positions that don't require such capacities.

As a side note, it is interesting to see that social activists are pushing really hard for women to be able to join elite units on a "free will" basis, but not at all for girls to be required to enroll into selective service.