Wow.. i really don't get the total opposition to this...
Everything is right there in the open... if it's not for you then understandably, don't participate, but i dont think anyone is trying to rip anyone off here...
Its no different than the majority of stock photography sites or most art gallery agreements... although with most of them, the artist has to substantially fund the printing.
This is of course, all based on the assumption that the creators of the website actually do what is said on their website. No contract in the world can protect you from being burned... it only gives you recourse in the legal system to seek compensation... which is probably seldom worth the trouble.
Bewildered I be.