playing soccer stirs our ancient hunting/chasing instincts,where the ball substitutes for the prey animal ! The action of scoring a goal substitutes for killing and keeping the prey as a trophy.The bouncing and rolling ball away from us at a fast rate of speed resembles a prey animal that is trying to escape.
Perhaps we were too quick to misjudge Luis Suárez then. He was merely getting in touch with his 'ancient hunting instincts'...?
Do you also have a theory for why the interest in the sport can vary so widely? Above data is from 2012 and 2014 respectively: (click to enlarge) The 'natural' interest in the sport can vary a lot.