that is not the point. The point is we don't need content nazis. U can go to Facebook and youtube if you want that. Here people can post and get rewards if others appreciate it and vote for it. The system has worked to the extend that nudity practically does not exist here.
The NSFW tag works pretty well imho. I think there would be even better ways to implement it, but I am worried when people come and want to censor content. If you don't like it, you can down vote.
However I do not understand your concern as anything with nsfw is not really visible and if nude stuff does not get the tag, it get down voted. what more do u need?