Why do mothers teach their sons to be nice...?

when that only serves to hamstring his chances of success with women? Society in general reinforces mothers bad teachings. Since reproduction equals survival, a son is already a risky investment for a mother to make because he may not be successful where a daughter is a more safe investment to successfully reproduce. However, with greater risk comes greater rewards. If he is successful he can sire many offspring(as males theoretically possess greater reproductive potential than females) and she can have a profound legacy in the gene pool. So why do mothers teach their sons counter productive lessons on how to treat women?