Isn't a child's phone a managed device? Using MDM for parental control seems entirely appropriate.
So by using it, you're giving some complete strangers access to snoop on everything in your child's phone. Even if you trust the developer not to abuse that, you're trusting them to keep their own systems secure and to not hire an employee who might abuse it. We know how that worked out for the NSA where they had people using their surveillance programs to snoop on exes.
If you want to use MDM to manage your child's phone, the way to do that is with a service where you manage the MDM yourself like a company would do with their fleet of phones, not to hand the keys off to an untrusted third party.
Ah. That makes perfect sense and I'm changing my mind on this one. Apple did the right thing.
Similar thing, I had a nest camera in my daughter's room when she was under 3. Now I've removed it, because she is old enough to have time to herself. I know one parent who demands to have a camera in their kids room and one of those kids is 14. That's beyond awful.