I always thought it was parents being competitive - especially for unobvious social status signals.

We notice competitive behaviours at our jobs - we expect to see it, and in many work situations competition is admissible.

It is harder to notice competition in our social lives because we deceive ourselves with rationalisations (that appear reasonable) and the games are less obvious.

Just a personal theory (I'm a late learner for even simple status signaling).

Could you put your child in a different school that didn't do that?

The US? My 2nd grader has one piece of homework per week, which takes about 10 minutes. If there was more I would tell the teacher to shove it. Instead I talk to my child. If he's interested we talk more about that, otherwise we switch to a topic that interests him. We've covered a lot of science, astronomy and math. Lately I've been telling him about primes, factorization and cryptography. I think our conversations lead to a love of learning and curiosity that is 100x more beneficial than a 50cm stack of homework...