Because women become pregnant, carry the fetus, give birth, has the abortion, etc etc.
If the woman lies about taking birth control, she's still the one who goes through this.
As I clarified to edgar, the discussion on another forum was regarding the pregnancy of the woman, a woman who has made it clear she did not want pregnancy for herself.
Although the man would be a father/father to be, that does not equal physically having an unwanted pregnancy, labor, abortion etc.
And, most importantly, on the other forum, it was not a "what if the genders were reversed" discussion. It was as I presented it in the OP.
The reason I presented it here was to see if in the general population, which A2k represents more than those on this other forum, would mirror each other.