I'm annoyed also about ebay auctions being posted, especially the FSS ones. I check ebay everyday for a deal, only to find towards the end of something I'm watching/bidded on, happy posts a link.
But that's only looking at a buyer's point of view. As a seller on ebay, It's really hard to get traffic on an item you sell on eBay by just posting it. It's very rare to really cash in on reselling your somewhat "rare" items. Posting on ebay isn't always just enough, heck, even posting on a few message boards could only make it at least close to "breaking even."
Luckily, the guy selling the Jagd book got his item posted on a msg board for fans of FSS that actually want the item. Why it got so high compared to Models/Kits? I guess the thing that popped into my head was "hey, I can always get a kit later but this is a rare find at least for me" since, I rarely do browse ebay I usually sell rather than buy so Happy posting it here did help both prospective buyer and the seller get what they both want.
No one likes to receive less than they what the paid for. The feeling of selling an item for half of what you paid for it does hurt the seller.