That's an excellent idea. I wrote the copy on that page trying to convey "can I get your help against these bad people?", rather than something blaming the user

That's an excellent idea. I wrote the copy on that page trying to convey "can I get your help against these bad people?", rather than something blaming the user, or a scary looking warning. But showing them the _reason_ why a certain website is blocked can become an opportunity to teach people critical thought, something that other comment threads point out.