Showing-off strength, reinforcing dominance and being ruthless were very important (especially masculine) human traits … to ensure survival. If not: one could go hungry, get hurt, lose their breeding partner or worse lose their life. So back in the Stone ages: One would kill & hunt when one wished; grabbed thy neighbour's food or partner if need be or just kill if one didn't like that jerk. So in a way life was quite ‘simple’ cause and effect J
Consider simple everyday things as a joke: realize that almost always a joke is centered on putting down one of the characters in the joke! Belittle, embarrass or ridicule. Funny isn’t it? Ever wondered why we crack jokes and laugh in the first place? It is our way of expressing our own superiority over the other. Baring teeth (while we laugh) is common in the animal kingdom also … for the same reason!