Granted I haven't read the rules myself in a number of years o.0... and it's grey area... but the 'no market place' not only means posting sales threads and directly asking for money (the main crux of the original ruleset no doubt... before my time here), but also means self-promotion of your own 'products' (on auction sites, among others).
While people do occasionally post ebay auctions, they are usually in reference to something an OP said and not the repliers own auction or sale.
I think it's just a slight misunderstanding on your part as, tbf, you have been honest about it being your auction. None the less tiz bad vogonian etiquette I'm afraid...
Couple of years ago there was a uber ebay thread (awesome I might say... but yes lived it's life and was rightfully nuked from the forum imo). Everything was fine and done in good faith at first, then it was noticed that some users were self-promoting and possibly click baiting to get revenue so it was shut down... then shite loads of toys went flying all over the place from some users and there was as massive fallout... hence the feelings by some about auctions being posted.
Certainly is fine to post old ebay threads of closed auctions, but not current. 😉