Is it part of the game or poor sportsmanship?

Not to duck the issue, but it's both. Many times a team can promote itself in the standings, whether it be the NFL or some smaller league, by scoring more points against their opponents. Many people may not be into the statistics which actually do make a difference in team's standings at the end of the year. Also, individual players need to promote their "careers" in the game, so, they score more to promote their individual players. I will agree that in younger age ball games, careers aren't an issue, and so it would seem to be unsportsmanlike conduct, but, again, teams run up a score to get them "high" for an upcoming game they may feel a bit inadequate for, and they have to psyche themselves up. I'm not denying that some teams/coaches run up scores that are unnecessary, as in when one team scores 75 points and the other scores 6 points (two field goals), and I've seen that happen in an NFL game: Dallas vs. Philadelphia, many years ago. I even saw a game that the ending score was 100-6, and we're talking football, and that was the University of Houston on one side and I can't remember who was on the other side, or who got which score. That score was ridiculous, and only individual players got special recognition in that lopsided landslide. But, at that age, all the players should be ready for a shellacking from time to time. It keeps them acutely ready to do their best so they won't have to face such an embarrment. Younger kids, however, should be saved from this embarrment, to a degree. If you shelter them too much, you deny them the learning of what the world really is like when they grow up and "come out from behind mama's apron strings". And from the situation as you told it in your question, nobody got shellacked. They just got stung from good competition. God Bless you.