Apart from the fact that the violence is far, far worse than pornography, I totally disagree.
But first: my credentials. I'm a father of two, and I've recently been visiting a number of schools seaching for a primary school for my eldest. My brother is a network admin, at a primary school. Part of his responsibility is administering the internet filters.
Frankly, children don't get to be on the open internet. Every school has a filter. At home, I've turned on safe search, locked down youtubes default settings, etc. Can children get around it? Absolutly! Part of my brothers job is to search through the network shares each month and remove the porn.
However, blocking 100% of the 'bad stuff' is not what this is about. Nobody is still stupid enough to belive that you can install some technological measure, that will stop everything. Espically, if somebody sets out to explicitly circiumvent it.
What this is all about is reducing the chance of in-advertant viewing. Kids like to explore. They will click on link, after link, after link. I'm carefull not to leave knives or sharp objects lying around my kids play area. Online, I would appreciate it if wikipeida took the same care. Your never going to stop stop somebody who is determined enough, but you can at least make a minimal ammount of effort to stop people randomly blundering into this stuff. Having the option to enable a warning before adult images on wikipedia would be helpful. At least I can teach my son that if he sees the warning and clicks 'continue', he will probably see something unpleasent.
As for the suggestion that parents "should monitor their children's online activity themselves" - the internet is no longer the PC sitting in the living room, where you can sit down for a family browsing session! Its phones, tablets and TV's. Its at home, friends houses, its at school and in shops. In 2012, "monitoring my childrens online activity" is already difficult. By 2017 is going to be impossible.