... I hid my thinking from them. Had I placed a public bid, I would have made my thinking public, and I would have allowed his thinking to color mine...
This is the part I don't understand. How is entering your high bid in eBay making your bid public?Nobody else can see your high bid, and you can't see anyone else's high bid.
Are you saying that the sniping programs allow you to impose a level of self-control that wouldn't be possible if you found out that your high bid was too low before the end of the auction?
I guess that's as good a reason as any to snipe. As you say, there isn't really any downside.