Whatever you think of the various sides of this argument, it's interesting to me to look at how different the sides are.
The US is, on average, far more concerned about pornography and other sexual issues than the UK, but there is not and never will be any significant discussion of government-mandated filters, outside of specific situations like government-run schools. The reason is our belief in the importance of free speech. Although there are plenty of Americans who would like to ban porn, no one at a national level says it out loud. No one seriously talks about it even at local, highly homogeneous levels, because everyone knows it won't fly.
The UK is somewhat less prudish than the US, but is perfectly willing to carve out large exceptions to free speech wherever it's convenient. Therefore, British pols do talk seriously about trying to ban porn, except for adults who opt out.
Europe (as a whole; there are exceptions) is even less concerned about free speech than the UK, but apparently considers porn to be something worth fighting for, to the degree that they're willing to invest at least a little effort in fighting to keep porn available to kids in the UK.
FWIW, I think porn is bad. Conceptually, there's nothing wrong with human sexuality, but porn presents an extremely distorted view of human sexuality. I think regular consumption of hardcore pornography, particularly by adolescents, skews expectations and perceptions in ways that have negative consequences. That said, I have no interest in trying to ban it. I do filter it on my home network, but that's a half measure which mostly serves as an early warning system (I get notified of attempts to get to porn sites) which offers a chance to talk the issues over if I find my kids looking for it.
All of which mostly says that I'm a fairly typical American parent: concerned about porn but unwilling to take the strong anti-freedom steps needed to effectively ban it :-)