It is very similar to people selling test equipment to identify a piece as "Hewlett-Packard HP Agilent Keysight" Clearly no piece of gear is labeled with more than one of these company names. But the description is "overloaded" (a programming term) to attract searchers for any one of the brand names.
Maybe we are coming at this from 2 different directions here. In the case of the example you give above, I'm very happy with that description, since HP changed to Agilent and then to Keysight and this is a way of informing people that equipment carrying any of these brand names is a good piece of equipment and embraces all the goodness of the original Hewlett-Packard brand and image.
The eBay listing for those record adaptors, to me at least, suggests to people that an adaptor that mentions Aiwa, will not work satisfactorily on a record made Garrard, BSR, Goodmans, Akai, B&O, Philips, Teac, etc which is utter rubbish.
I sell items on eBay myself and I have never had eBay take it upon themselves to alter my heading and or the description of what I sell which leads me to conclude that the entries have been produced by the seller themselves.