Hacker News Reader

It establishes the expected behavior. You're absolutely right that it doesn't teach sincerity, but that's not the point. It builds the habit, and it forces acknowledgement that another party was harmed (even if they lack the empathy to care about that yet, empathy starts with awareness).

Sincerity is largely learned by example. It's important for parents to model sincere apologies when they screw up. To each other, to their kids, etc.

I agree with this sentiment but I think "apologizing even when you don't feel like you did anything wrong" is the kind of dishonesty that's absolutely necessary to get by in society and that you should definitely teach your kids.

It’s also about showing the sibling that was hit that you as a parent consider the behavior unacceptable. They need to feel that grownups react, even if they realize the apology is fake.

Absolutely not: it's essential, because all but psychopathic people learn how to do things for real by going through the actions. This is essential training.