Except the domain name is not their property, it's Ron Paul's trademark. It'd be different if ANOTHER Ron Paul was using the domain, but clearly that's not the case. If you go to ronpaul.com you'll see Ron Paul's face and quotes being plastered over the merchandise they sell.
They are violating ICANN policy and trademark law. Plus, being completely douches for trying to sell Ron Paul the domain name for $250,000 - when it only cost them $10.
Ron Paul is in every way shape and form justified for doing this. He's both legally and morally right, it'd be difficult to argue otherwise.