oh, i know.  and all gallery sites i know of have the same rules, so i don't think Rendo is unique or uniquely responsible.  personally, i wouldn't say it has to do with Puritanical attitudes.  the porn and sex industries are far more legitimate industry ever before,  and prime time goes much further than when i was a kid.  to say nothing of premium cable channels.  i think the problem is much more basic than that.  i think the U.S. has created  a culture where someone is  always responsible if something negative happens, and you should always prevent negative things from happening.  combine that with the fact that the whole Web media revolution is about untrained, average individuals posting and commenting on work, and you have a situation where sites have to account for the most flagrant offenders and the most easily and wildly offended.  there's no concept that people should be responsible for their own viewing habits, and certainly none that maybe being shocked or uncomfortable when viewing art isn't necessarily a negative.