Ironic from him, eh?
I'm sure that was said before his foray into elected politics. Still, he didn't run for president though his going for PM was a disappointment. HIRH Archduke Otto said something similar and he too renounced his royal position to run for political office. The temptations are great it seems...
I actually just quoted His Imperial and Royal Highness in an essay I was writing on the Habsburgs for one of my classes. He said "Once you have tasted the opium of politics, you never get rid of it." It's a shame such great men such as these were forced to bend to the ills of politics. The Archduke in particular would have done splendid things for Austria and Hungary, I have no doubt.
I think they both just had such a natural compulsion to be of service to their country(ies) that they couldn't help themselves. As widely popular as they both were, the public is so irreversibly brainwashed into republicanism. Restoration of the Hungarian and Romanian monarchies appears to have never even been considered after Communism (outside pressure might have interfered). Otto and Simeon II probably just figured that if they ever wanted back into government, doing so as an MEP and PM was the only way it was going to happen. Not that I agree with their decisions, of course, politics is justifiably beneath the dignity of royals, but I can at least understand some of their thought process.
I think that it is diferent doing politics and being a politician, the monarch must be always in politics, because his reason to exist is rule the country. So it is an error to say, like say some monarchs and pretenders over there, that the monarch is superior to politics (that sounds me like an republican excuse to keep them out of politics, and that is my problem with the modern constitutional monarchy, the inaction, voluntary or forced of the monarch), he is the absolute ruler of the country so he will be in politics during all his reign. Becoming and president could only work if you wan't to imitate Napoleon III, and then making some kind of coup, popular aclamation or wathever. If not he must boycott with huge ammounts of propaganda, gather support of important people, etc. And it is always possible to follow the jacobite style. But i think that being a constitutional figurehead can't be an definitive aim of a good and faithfull pretender. Hi from Argentina.