No the human race wasn't defenseless before gunpowder, but brute strength counted for a lot more in any confrontation. If a 250 pound, 6 foot , muscular man has a dagger and is attacking either another man or a woman of 125 pounds and less fit, also armed with a dagger, who would you bet on ? Change the weapons to firearms and relative size andd fitness are much less of an issue.
Instead of crossing swords with an attacker , it is simpler to use the "Indiana Jones response".