[corobo]

"The 4xx class of status code is intended for cases in which the client seems to have erred"

vs

"Response status codes beginning with the digit '5' indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request."

There's always that quote people chuck around a lot about censorship being an error so the internet routes around it. By that definition the server knows it has errored so it should be a 5xx response.

[Nerdit: Fixed the quote marks]

[drsintoma]

I'd consider it as much of an error as a 404 in this context.

1) Link works: 200

2) Take down notice arrives

Now:

3) Link not found: 404

Then:

3) Link not available: 451

[Terretta]

I'd argue it's a client error. Whoever's hosting the info is happy to host it, while the client needs to go vote out the politician that censored it.

[mpyne]

What if the client is not from a nation that is causing the server to refuse to serve the content? It's very much a server error.