I was gearing up for a rant about how this hurts the open internet, but after watching the video, it seems fairly well reasoned. I guess it all pivots around how effective the review panel is at unblocking access to sites that have been miscategorised and how easy it is to enable and disable the filtering.
except you cannot unblock sites you never get to see in the first place, and thus remain ingnorant about their very existence
If you don't know about a site you don't care if it's blocked or not. If you do know about a site you'll find out if it's blocked as soon as you try to visit it.
Explain the difference between website discovery pre-block and post-block? How would someone before the block discover a website, and why wont that work after the block?