The action eBay will take is a mark against the sellers account. I think it's 2 marks and your account is given sanctions such as restricted selling or buying. I'm not sure with the quoted text why eBay are saying they are dealing with it but I suspect you have received an automated response worded exactly the same as if you had bought a dress.
Imagine you went to look at the car because the seller accepted your bid. Imagine that when you arrived to collect the car there was a massive dent in it or it wouldn't start or a huge oil leak wass apparent, would you have handed over your cash? No, so that clause is effectively the buyers get out one, and is just letting the seller know that. But it also works for the seller too.
There is a Cars and Motors discussion forum on eBay itself and you may find that very helpful, but seriously, I would stop letting this spoil your day and move on. You're miffed because you missed out on a bargain through someone else's inefficiency and whilst unfair, it is not something you should dwell on
Good Luck