When eBay places bids on my behalf they are acting as my bidding agent, in my opinion.
Once the shill bidder made his fraudulent bid, my agent -- acting prudently, would not bid again on that item. The sale and the pool of bidders and sellers in it are now tainted by fraud. In this particular case, my maximum bid is now public. In such circumstance a reasonable buying agent would not rebid at all on the item. Yet Ebay does, that is imprudent and is not only a practice that allows fraud -- it is a practise that REWARDS fraud.
Do NOT miss that that in this auction the was a clear pattern that drew the strongest of suspicion of fraud upon the seller himself. No one -- you included -- should buy from frauds!
Especially not on Ebay, where the item being bought is not present to be examined.
eBay doesn't broker or bid for you. You are doing that.