I'm not sure I see it that way, the guy says he sold it after drilling the hole in the bar and putting motor oil in it, if it oiled like that, what's the issue?
I list things on CL all the time for twice what they're worth because everyone wants stuff for free. If I expect to get $100, I list it for $200 OBO.
Every so often someone comes along and pays the asking price. That's not my problem.
The sticker price on a brand new MS250 down at the local dealer last week was $299.99, that is for the saw. No case, no extra chains, no bar oil, no 2 stroke oil.
Its got a big sign over top like its a sale price. They were $349.99 a while back.
The guy said he didn't have much use on the saw, so if it was indeed as clean as he said, I don't see why any would expect to get any less.
If I buy a new saw, bring it home, cut a couple boards with it and decide I don't like it, are you supposed to sell it for half of what you paid.
The store certainly isn't going to take it back after its had gas in it if its not defective.
With all that said, I didn't get anywhere near that when I dumped mine, one got sold to a guy who I see all the time, he loves it, he put some huge oversized handle on the saw and carries in the back of his pickup truck all the time. It looks like it fell out of an airplane from sliding around in the truck all the time. He gave me $150 for it two years ago and thinks I gave him a deal. It was a bit battered then but it ran if you didn't mind ripping your knuckles out trying to start it. The thing must have had 200 psi of compression.
The way I see it, the guy lost more than he made on that saw. With buying a couple of bars and chains, and it sounds like he also bought a case for it, he's likely in the hole a few hundred bucks or more even after selling the thing. If he gave the thing away he'd have lost even more. What he should have done was dump it from the start and not put a dime into it. Then he'd likely only be out the difference between what he paid and what he sold it for.
I think he got lucky and got out from under it, when I decided to dump mine, I had trouble getting half what they sold for new. I hated the saw, it felt like it had 200 pounds of compression, it took a gorilla to pull the rope. The guy who I sold the one too loves it, he tied a homemade wooden handle to the recoil rope and carries the saw with him everywhere he goes, its been sliding around in the back of his truck for over a year now. Everytime I see him he brags about how great a saw its been. To me, that thing was a mess. It didn't oil well, it was hard to pull, it lacked power, and the .325 chain never seemed to last very long. I owned that one for maybe three months and dumped it.