... perhaps, they don't really want to understand ...
Quite correct, unfortunately: there are only two issues of interest for ebay - the sellers' fees, and not getting sued for allowing forgeries to be sold via ebay. As nobody in the paperweight business is willing to sue them, the only point left are sellers' fees! As long as they get their money, they don't care.
I still occasionally report a fraud - resulting in the standard response that "appropriate action" will be taken (they obviously consider nothing as appropriate), but I cannot be informed about the outcome, as the fraudsters (well - they don't use that word) privacy needs to be protected.