What exactly here is offending your principals? That Ron Paul wishes to enter arbitration? He isn't trying to sue or take by force anything. Arbitration is the cornerstone of any sort of libertarian contract law. We have no idea what sort of arrangments or agreements they have had now or in the past. Clearly there is something or he wouldn't be trying to go into negotiations (arbitration).
Even if they don't have any agreements, Ron Paul is asking for arbitration because he believes he has enough of a legitament stake in the URL to enter negotiations over it. I believe he does as well.
The people making money off of RonPaul.org/.com only have this income "because" of Ron Paul. He is the product they have been selling the entire time. They want to charge him $250k for a website that would be worth nothing if not for the man who they are trying to gouge over it?
I don't think Ron Paul has a legal case here, but then, he's not trying to sue is he? Arbitration is the better option, and is valid. Clearly these guys are assholes, and no one can force them "not" to be assholes. If Ron Paul was trying to use force to take the URL, that might be one thing. However he's not. So what we are left with is a couple of parasites who want to make it harder for Ron Paul to carry on the fight. It begs the question, did these people ever care about the cause, or was it just a money making stunt? There's nothing wrong with making money, however I will certainly be looking elsewhere next time I want to buy something for the cause.