I like Paul's suggestion of writing them to challenge it. You never know. When I was applying for schools I got a rejection letter from the one program I really wanted to get into. So having nothing to lose I wrote them a letter back, tactfully rejecting their rejection letter stating reasons why. Two weeks before the semester started they called me in for a meeting. They reversed the decision :-)
Here is their policy page. Notice the criteria. Yes, we MUST protect our children from simple nudity (sarcasm).
http://www.flickr.com/help/filters/