Although the police may take photographs of murder victims, it is generally not appropriate to view mutilated bodies while at work (unless you're a cop, etc).

I do think it is a bit silly to want to call the pictures from the scanner NSFW, because they're clearly in the context of speaking about the TSA rather than for any prurient reasons. If I wanted to see fuzzy outlines of genitals, I'd grab a pencil and sketch them myself.