Is 4chan the perfect Pirate Bay poster child to justify wider UK site-blocking?

The game Alpha Centauri had the most hard hitting quote that I think applies now.

"As the Americans learned so painfully in Earth's final century, free flow of information is the only safeguard against tyranny...Beware of he who would deny you access to information, for in his heart he dreams himself your master. Commissioner Pravin Lal, 'U.N. Declaration of Rights' "

Have you considered parenting your children instead of letting the state do it for you? The latter means they can use the good old “for the children” rhetoric to control what adults can and cannot see: for example, they can choose that homosexuality is a sin and bad therefore any LGBT friendly website is bad. Apply freely as your government dictates, such as pro-Palestine content. We must protect our kids from terrorists, after all. :)

Meanwhile your children are absolutely going to find a way to get that content regardless, likely in darker corners of the internet, exposing them to much, MUCH worse content than if they would have just gone on the good old hub (plus actual predators) while also making it basically impossible for you to control instead of just making it a firewall rule away from locking it yourself instead of letting the government do it.

I don't understand why you see these as either-or propositions. It's important that I parent my children to understand the dangers of alcohol, and it's also a good idea that it's illegal for my local grocery store to sell them any, and neither of these are contradicted by the fact that they'll be able to find some if they really want to. Norms and friction matter.