I personally think this is an OTT reaction.  It is not as though you listed with '100 available' or anything like that. 

So it effectively means that if someone has made a legitimate purchase at some time, decides they no longer want it after it has sat at the back of a cupboard for years, and would like to recoup some of their original expenditure, (particularly) if it is still got its original packaging, then it can't be sold on eBay.

I wonder how many eBay sellers would come under this 'listing violation'???