I could care less that it is not working. There are tons (30+) of small components and screws that are missing that were not listed.
No.
Just no.
I've bought my fair share of broken equipment on eBay, and yes, I've had this happen to me as well.
One member here that is in computer repair put it very succinctly. I am paraphrasing, but what he said is that most, if not all of the time eBay is not the first place people go when their computer dies. Which means eBay listings are generally after the repairman has deemed it not worth it to fix (or screwed it up).
Which means, that if something is listed as "for parts or not working",
be prepared for anything. Some of his stories are like yours (and mine). Some idiot with a screwdriver decided to go all gung-ho and rip connections out and go crazy with soldering. Also paraphrasing, but eBay is probably the most crap-tastic place to buy broken computers ever. Don't do it unless you have to.
I'm fairly certain that people are not obliged to include any information about an item listed as "for parts or not working" other than it does not work. Remember, anything goes.
So if I listed my computer, which has had more than it's fair share of rebuilds (literally the only things that have not been replaced are the battery cable and motherboard), would I have to list that I think a component is missing on the bottom left side of the motherboard? Or that 5 internal screws are missing? Or that the screen has a slight dark ring in the center? Or that the backlight fuse has been replaced?
If I listed it for parts or not working, no. 99% of people on eBay have neither the experience, nor the time to list (or even know about)
every single thing wrong with a computer. Sure, it would be great if they did, but really? For all you know they took their computer to their "genius" geek nephew who proceeded to ruin it and lose a bunch of screws and call it toast.
Unethical? Maybe. A problem warranting an eBay case? Hardly so.
Edit: perhaps including the listing here might gain you some support.