Betsy Newmark talks about the matter.
School sports remain an important part of the education system and I fully endorse that aspect. But academic competitions are also important because competition does not have to take place only on a sport field. There are only so many slots on a given sports team and not every can make the team. But sports are encouraged and academic competitions are not.
One reason often given is the effect on a student's self-esteem if they lose. But sports teams regularly lose and individual kids lose by not making the team. Seems to me that the hypocrisy is pretty ripe on this issue.