You can't kill someone with a smartphone though.

Unless it's a nokia 3310 and you're like really strong.

It's more akin to an adult lecturing you about the harms of junk food and controlling everything you eat while they themselves eat nothing but cheetos. It creates an adversarial relationship. You can rule as a tyrant, but it's not that pleasant for those that have to suffer through it. Obviously there are outlier exceptions (drinking, driving, very young children etc.) but even those are mostly for societal consequence reasons vs. individual capability.

Kids pick up on this hypocrisy and it can backfire: https://en.wikipedia.org/wiki/Reactance_(psychology)

Autonomy is really important - being empowered to actually make the good decision.

It's a matter of respect imo, adults often have too little of it. The best teachers I had, had a lot of it.

Kids observe, if you tell a kid to be generous but you behave selfishly the kid will assume you're full of shit and ignore what you're saying. The opposite is also true. Talk is cheap, what you actually do is what matters.

Similarly, the emergent generation in American often reject learning to drive a car, as renunciation of the anthropocentric lifestyle.