He didn't give us "free will" to do evil?
He gave us free will to freely choose good, not to do objectively evil things without other people interfering.
it is not intrinsically evil there is no law of man or God saying women are forbidden to serve their country.
It is intrinsically evil for women to be "soldiers" - it's not about serving the country. The roles between men and women in the military have been hopelessly blurred. It's entering an occasion of sin, for an illegitimate purpose, to be a female "soldier."
The military culture is godless and corrupt. But it's full of strapping young men. What kind of parent could tolerate their sheltered daughter going into such a miserable situation?
Only a parent who really doesn't have Catholic values.