Does the registrant of RonPaul.com own the Ron Paul brand and trademark?
They were fine having the domain name and running it as a fan site. Where they went wrong was when they tried to sell the domain name to Ron Paul.
That's how it works with domain names & trademarks online. Law has been fairly clear on this for more than a decade.
You cannot register CocaCola.com and sell it to the Coca Cola company any more than you can register domain names of famous people and try to sell it to them.
Yes, fan sites are OK. However, running a fan site does not somehow create an exception where the fan site owner can then turn around to sell the domain name to the famous person or someone else. If that was the case domainers would have registered famous names by the tens of thousands & there would be fake placeholder fan sites everywhere to circumvent this area of domain & trademark law.