Neither should, both can and do.
However, from a lot of parents, with boys, the "do NOT hit girls" message is massively amplified.
Both genders will break the rules, to some extent. When a boy does it to them, by hitting, they can respond, if required. A girl who does the same can find a convenient physical and emotional punching bag, when the "do not hit girls" training ends up locking up their defensive response.