It is very natural for kids and teens to test their boundaries and try to get as much access and control over any system that they could get into. And from a kid perspective it doesn't feel like a particularly dangerous or wrong thing to do. Hacking into stuff feels just like an elaborate and very rewarding game. Game that requires specialized knowledge and skills, but a game nevertheless. I think we all remember the feeling.
But in reality this is not a game. Damage that can be done by an accident involving a such a game/hack that goes awry can be catastrophic. That includes loss of life and likelihoods of a large number of people.
Examples? Say, can a hack interfere in a subtle way with remote surgery? Or with hospital power supply? Or chemical plant? The answer is unfortunately, yes. Our systems a networks are not secure enough and not kid-proof. And probably will never be. So there must be some policy that discourage kids from hacking into stuff that matters. And yet it should be friendly, because it is preposterous to put people in jail for 'games' that are very unlikely to cause any harm most of the time.