Regarding the category-specific severity levels (instead of "low", "medium" and "high): The three levels currently used are definitely not completely arbitrary

Regarding the category-specific severity levels (instead of "low", "medium" and "high): The three levels currently used are definitely not completely arbitrary. I'm sure we all can tell mild violence and really severe levels of violence apart. But I definitely see your point, nonetheless. For "nudity", the different levels of "bare buttocks" versus "full (frontal) nudity" come to mind, for example. This caught be implemented in custom severity levels, of course. But the major advantage of the three general levels is that the higher ones include the lower ones. That makes things as easy as choosing one severity level for each category. If, for "nudity", you have the two levels suggested above (and potentially dozens of other levels), you have to provide a check box for every single level or "sub-category". That's far more complex, both from a consumer UX perspective and from the tagger experience.