Because of the biological asymmetry between the sexes. A man can have thousands of children, and women can only have a small amount. It's what drives natural selection and evolution of the species. Some part of the men are supposed to get rejected.
What do you think throughout history the men that could not find a match did? They joined wars, became vagabonds, thieves, joined piracy or similar and went to forcefully acquire wealth and/or women (and rape). Needless to say a peaceful nation does not want that. Men are going to fight the rejection tooth and nail (a trait evolved in a similar fashion).