Most parents behave protectively towards their children
And that's natural. To be honest, I'd prefer having overprotective parents, who might buy misinformation in the process of protecting their kids, than careless parents. The overwhelming majority has bought that bitcoin is bad. It's natural for parents to reinforce that opinion to their children, even though it's bullshit. As a result, such parents, through their unreasonable guardianship, try to protect their children from a useful and unique financial instrument.
not to mention the fact that this requires cash injections, which undoubtedly pushes people away from their passion for the bitcoin.
If it pushes away parents themselves, imagine what their response would be if their children asked for permission to hold bitcoin, provided that they live with pretty much their parent's money. 
Only a few will approve of children's decision to invest in bitcoin the money they received from their parents. But these will have to be very progressive parents. For example you, reader. How would you react to such a desire of your children?