I actually agree with the idea of an ISP based filtering service, providing that it's opt-in for customers (heck, why aren't the ISP's offering this as a chargeable add-on I'll never know). Not everyone in the world is technically literate, and anything that makes it easier for parents to make valid choices for their children is a good thing.
Unfortunately, this moderate middle ground is getting swamped by the "Censorship is evil" vs "Porn is evil" battle, and both sides are ignoring their chance to compromise.