I wonder how many adults here saw porn as a kid? If we're being honest, probably the majority. Kids don't find youporn unless they're looking for it.
There is a highly effective way of preventing kids accessing porn, by being a parent and watching them (ie, put the computer in a public area) and also installing porn blockers in parallel. That's the solution.
The problem with laws like this, is that they're easy to abuse and they're created by people who don't understand technology either (so they're happy to make tech less useful, or they'd even ban some of it entirely if they could be to level the playing field).
It's more important to keep kids away from unsolicited porn specifically and creeps, and that can be some simply by requiring a site warning and monitoring them online