When one of my kids was five or six, he was an animal on the soccer field. His parents told him to back way off, and he never really was a useful forward for the rest of his "career" (through 1 yr HS). In fact, he eventually dropped out of soccer but basically became a defenseman in water polo and lacross.
It'd be better to have a mercy rule to just stop the game at some point (with the concurrence of the lower scoring team's coach).
Yes, when I coached, I recall there was a 10 run slaughter rule in effect to prevent these types of blowouts (in baseball).
Competition is good, but running up the score like that is questionable. In the pros it is a different story. I remember last season some people griped that Belichek ran up the score a few times, but if you are getting paid to play, then it is your job to stop the other team.
But for some people, it is more difficult to accept a loss by the score of 60-59 than it is to lose 100-0.