I totally agree on what has been said about the policies of ebay: it will be futile to try and make any sense of why the pull an auction down or not.
I have had some auctions of cigarette picture albums stopped by ebay, while others were selling the same thing at the same time. And trying to ask ebay the why's and whereabout's will only result in standard generated replys.
As you said: they call the shots. We just have to adjust to it :-)