You seem to be mixing two rationales in there: 1. That TV and cinemas are not allowed to publish such material. That just pushes the question further back dow

You seem to be mixing two rationales in there: 1. That TV and cinemas are not allowed to publish such material. That just pushes the question further back down the line. Why should such content not be broadcast? 2. That minors might be exposed to it. Minors should not have unfettered access to Facebook and YouTube anyway. The consquences of displacing the proper locus of control from parent to state ends up making minors out of all of us. (Note: in this case I do not believe that there is anything to be gained from watching such videos -- I may be wrong. The objection is that, as always, the ability to exercize such control in the hands of government means that other, potentially more important information becomes censorable.)