Sure, but how much trouble would it be to allow those who don't want to do it to sit in a classroom and do homework or study instead while those who do want to do it, do it.
Anyone could tell you that there is no point to forcing someone to do something that they are dead set against--it only ends up ruining the activity for others and certainly does nothing to make the person who doesn't want to do it feel any better either.
Sport is great for those who enjoy it, but again, it has no bearing on a person's academic career and should not be forced on anyone who doesn't want to do it.
And anyone can tell you that it's often not quite as easy as simply finding another school. Life often isn't quite that convenient.
Many children also have insecurity issues with their bodies, forcing them to go through this sort of humiliation does nothing to benefit anyone and only serves as another demeaning act of "acceptable" bullying from adults.
It's stupid and unjustifiable.