>For a start, child are parents responsibility

And not distributing porn to children is a porn company's responsibility.

You are repeating a very common talking point but its not a good one.

Age verification laws make it possible to hold services providers liable for breaking the law (it's already illegal to distribute porn to minors in many places, like the US).

It's both true and completely irrelevant that parents should do a better job protecting their children from harmful services online.