but neutrally decidable criteria like "depicts nude female breasts", "depicts the face of Muhammad", "depicts mutilated dead body".
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User:Slomox
All of these would be problematic; if these were the default criteria for a school to enforce on their pupils when using school computers, one could imagine images of many 18th century paintings or depictions of gods being excluded due to "nude female breasts" and one would have to exclude all photographs of ancient Egyptian mummies as they were all "mutilated" as part of the process for embalming.
Cheers, Fae