An experience I had with a seller.

Shake it off. The dude is just veneer - you scraped past that. 

Guy sounds like a Schiit head.  He should have known those guys were from Theta and Sumo and are legends in audio ....  shifty Mark Schifter was the guy from Audio Alchemy Perpetual and AV123....not quite a legend.   Legendary for screwing people.   I think through a "charity"  scheme,  not a good guy.  

Guy is obviously a rookie.   

There are always two side of the coin. And I will be neutral in my response.

@mrdecibel 
If you stick your nose into someone else’s business you will, on occasion, be told to go eat schiit. This shouldn’t surprise you and or upset you. 
These are for sale ads of used audio equipment. Whatever the back story is, it isn’t going to cause physical harm, and you don’t know if the story is true or not. 
You should probably find better and more productive options to allocate your time to.
 

I sympathize with OP.  If sellers are using incorrect information, what he did was reasonable.  He gave the seller the benefit of the doubt that perhaps he had made an honest mistake and offered to help the seller from misleading customers.  This is all laudable.  The sellers response indicated that he had no interest in being honest with customers, and that is disturbing 

Agree with Mahler123.  I recently responded to a classified ad from a dealer, he was selling a 7 year old amp and had it graded as a 10. I simply said that a 7 y.o. piece should not be graded a 10.  His response :  " THEN WHY DONT YOU MAKE AN OFFER ! "   WTF?