It's not against rules for auctioneer to transparently bid on the auction. In my opinion, there's nothing scammy about it either. I asked theymos too, and he agrees with me. I understand the initial reaction may be "ooo, that's scammy" if it's an uncommon auction practice for you. I know it's uncommon in these forums. However, it's a common practice around the world. It's kind of a hidden reserve price.
Are you kidding? It's shill bidding; it's dishonest; and the biggest auction site in the world--eBay--doesn't allow it, and that's for a reason. It's inherently unfair, and I don't care if Theymos agrees with you or not. He's not an auctioneer. He's a forum administrator who tolerates scams by inaction and allowed the forum to become a spam pit because it brings more traffic.
Well, shill bidding would require usage of alt accounts or asking others to bid on an item to fake interest. It's semantics and I don't call auctioneer clearly bidding on the auction as shill bidding. Neither does Ebay. For examples of auctions where auctioneer bidding on auction is common, check out
https://en.wikipedia.org/wiki/Shill. Also check out
https://www.ebay.com/help/policies/selling-policies/selling-practices-policy/shill-bidding-policy?id=4353#section2. The Wikipedia article states: "One Proxibid auctioneers' website states, "At the request of the auction company, this auction permits bids to be placed by the seller or on the seller's behalf, even if such bids are placed solely for the purpose of increasing the bid."". Ebay link states that bidding on the auction
with another account is prohibited, as that's
shill bidding. Auctioneer bidding on the auction on the other hand is
not shill bidding as no shills are used and it's very transparent to everybody who's bidding. As I said, it's a form of a a hidden reserve price and is not considered untrustworthy behavior in general. I see your point too, and I very well acknowledge the benefits of e.g. stating clearly that a reserve price exists, if it exists. Etc.
So it's not dishonest, as you claim. It's not unfair in any way either -- auction rules are same for all. You could state that it's unfair, because auctioneer is the only one aware of hidden reserve price existing, if it's not disclosed. But what is unfair in that, really? At worst, it wastes peoples time when they bid and don't know about hidden reserve price. Auctioneer only knows that he will bid unless the hidden reserve price is met, if auctioneer wants such to exist. I think you need to re-think your logic regarding this. Vod did, too.

People on this forum have some shady notions of how auctions and escrow are supposed to work. That's why Quickseller has so many supporters for his "self-escrow" scamming. It's crazy that people don't see how dishonest these practices are--but not surprising on this forum, where every other member is a scammer.
The feedback you got is well-deserved. End of story.
Self-escrowing is untrustworthy and dishonest behavior, as that kills the whole idea of escrow. This thread is not about scams people do.
I understand it is hard for people to distinct between "subjectively unpleasant" and "dishonest/untrustworthy". Most of the time, people are too proud to change stance after thinking further and realizing how things really are. Vods feedback towards me is not deserved, is reasoned with complete bullshit lies, and is abuse of the trust system.