You have just made an effective argument agaist fighting in the first place.
A long time ago, if you had a serious beef with someone, you could have a duel. In that event, one or both were maimed or killed. Either way, it was settled then and there. Pride & Honor prevented people from making or accepting challenges they were not willing to meet. Right, wrong or indifferent, it was a simpler time.
Now, if you get into a fistfight with someone and beat them, you run the risk of them coming back with their friends or a weapon.
Compound that with the risk of injury to yourself or them for which you may incur liability or criminal consequences.
This in itself is a strong statement for fighting as a last resort, when violence appears imminent.