No one hates that women can continue having babies into their 40’s as much as men on the internet who throw tantrums about women not having enough children.
A woman can type "I hate men" while being with a man because, for women, "I hate men" means "I hate rapists, potential rapists, fuckboys, and ill-mannered men." That phrase does not refer to respectable men(it's hard to find).Maybe her partner is none of those things.