I am sorry for what happened and understand your frustration. You could have punched him in the nose, but I guess him being a lawyer, it would not be a good idea. I guess he could have lied and said he did not like how your gear sounded. Now I guess you know how salespersons feel. I don't bother with people who want to demo stuff first, except in one or two instances where it was not an inconvenience to me. In those cases, I actually enjoyed meeting these people and got to see what others had for systems. (They were just expensive interconnects) In another case I invited a person to my house to hear some B&W Matrix I was selling.
Most people (myself included) will buy gear to demo and then resell if the gear does not work well in our systems. The trick it to buy something cheap enough, so you can get your money back.
I also avoid folks who want to trade gear. If they can't sell their component, to raise money to buy mine, why should I get stuck with something they are too lazy to get rid of. I alway get the feeling their gear is in poor shape.