It seems like there are several scenarios that may have occurred:
#1. The dealer is authorized by McIntosh and there is not a local dealer option for the buyer. In this case, were the trans-shipment rules violated? If not, then McIntosh needs to review their treatment of their customer. After all, he did create revenue for Mc when the dealer replenishes revenue. In other words, if no rule were violated, it's reasonable to be upset that McIntosh wasn't more diligent in assessing the situation vs. citing standard "boilerplate" response. But it also seems the dealer should intercede as well--even offering to issue a refund upon return, and then he can deal with Mc.
#2. The dealer is authorized, but there is a local dealer option for the buyer. In this case, seems to me McIntosh should punish the dealer, not solely the buyer. In this case, the dealer might have been more pro-active and done their own research to verify no local option--McIntosh does have a dealer locator on their site. But it also seems the dealer has the responsibility to know and observe the rules.
#3. The dealer isn't authorized. In this case, the buyer has to assume the responsibility for purchasing gray/black market and not conducting some due diligence.
A very good friend of mine just purchased a McIntosh amp from a dealer, but verified that dealer's authorized status, both via the website and with a call to Mc. The staff there were quite helpful, even sharing the date of manufacturer, etc. In other words, it can be done.
I guess all I'm trying to say is that the OP doesn't have all the details needed to truly assess responsibility.