Even if the GCs give the most demanding curriculum for taking Calc AB/BC, these parents, wouldn’t believe that anyway. At the risk of generalizing, these parents are mainly Asian, if not all Asian, and they think only one subject is important for admissions - math! So they get bent out of shape if their kids are not getting homework in second grade. They make their kids accelerate in middle school, have them take the class in the summer if they’re behind (meaning not on track for BC as a junior). and place out of that class. Some high schools don’t allow this, so that’s progress.
Do you notice there are no threads on "I’m worried my kid is taking APUSH as a jr, will that hurt his/her admissions? It’s all about Calculus. That being said, there are some kids who can handle the math and want to accelerate, where the parents are not forcing the issue.