Jerry,
A direct link to an eBay auction is only useful to viewers in the next few weeks. eBay deletes auction information after a few weeks.
Stovebolt.com posts/threads are read many years into the future. Today's auction will be of no interest or usefulness next Spring or thereafter.
This is the logical/rational non-arbitrary reason for not being allowed to post eBay and Craig's List links outside the Swap Meet Fora.
If you post the words to search-for on eBay, that might be very helpful for future readers?