I applaud Tesla for doing what they can to prevent this kind of behavior, but I don't really blame anybody for wanting to make a buck off of the high demand. It should be really easy to buy another Model 3 in a year or two.
While the seller may be getting at least a stern warning at a minimum for this, there are plenty of people out there with money to burn that would love to show off their super-rare hottest thing. The Model 3 is that, I have no doubt he could sell it for that price, at least for right now while production is effectively stopped.
Major manufacturers routinely snap up the first available competitor cars so they can dismantle them to learn things about the manufacturing process, materials, design, etc. $150k would be quite reasonable to them.