It's likely that the parents don't even know the kids have a school email account, never mind who hosts the service.
You say that in response to me pointing out my local schools send and authorization form to parents...? I doubt there's a school anywhere that's stupid enough to give kids an email address without parental permission and signing of a waiver. All it takes is one precious snowflake unexpectedly getting porn spam and the school is in hot water. In loco parentis doesn't mean schools can do whatever they want.
The state, in removing that man from existence, isn't preying on some randomly chosen innocent stranger
You say this as if it was true 100% of the time. Sadly it is not.
Computer Science is merely the post-Turing decline in formal systems theory.