Speaker purchase question

They were rated a 7.

“Btw, did the ad say that only what is pictured is included? If not then it's his fault again”

No, this was not stated.

IMO, best practice: anything that was originally included by manufacturer and is not present at resale should be explicitly mentioned.

That said, the grills were not pictured, and seller did not actively mislead, so he's got a case; I doubt what happened rises to the level of fraudulent misrepresentation.
(A friend of mine one sold a very old BMW 5 series, and the frame broke the next day.  In small claims court, the judge ruled that to get relief, the buyer would have to show that he was *prevented* from inspecting the frame.)

Perhaps a fair solution would be for seller to offer some consideration towards new grills (50%?), so everybody could walk away feeling reasonably whole.
I'm optimistic about  such a concession, though, esp. since the cost of replacement grills might be extortionate,

“Perhaps a fair solution would be for seller to offer some consideration towards new grills (50%?), so everybody could walk away feeling reasonably whole.
I'm optimistic about such a concession, though, esp. since the cost of replacement grills might be extortionate”

The seller has pretty much said “too bad” and moved on. I don’t think I’ve ever left negative feedback over the past 22 years, but this is the first time I’ve considered it. Don’t know if it’s worth the trouble at this point. While I agree that there were no pics of the front grilles (the side grilles are present) in the ad, I feel it was sneaky, at best, not to mention that they were missing. The title of the ad referenced upgraded tweeters, so I thought the grille-less pics were meant to highlight that. The whole point of feedback is to warn future buyers...

Live and learn.  The fact that he stated that the tweeters had been “upgraded” should have been an obvious clue for you to be particularly cautious and inquisitive.  You were not deceived.  You, as the buyer of a used product, should have been more careful if the grills were that important to you.  Move on, enjoy your speakers and don’t let this sour your listening.  So, how do they sound?