Magneto isn't Malcolm X, as he's oft been compared to. He's George W. Bush.
Charles Xavier is the one, who while preaching for equal rights, kept ready a militant faction ready to enforce that princple. He's Malcolm X. And because of Xavier's own martyr complex, he'd be ready and willing to die for it, as has been shown on occassion. Not so with Magneto: oh, he has zero compunctions about sending OTHER people to die for his cause, but in every instance where he's been offered the opportunity to achieve his goals, but at the cost of his own life, he's managed to find a loophole or a way to back out of it. Nowhere was this depicted as clearly as in the first X-film. His principles are only as rigid as his ability to obtain them without much in the way of sacrifice.
In that regard, he's nothing but an egomaniacal thug and honestly, a terrorist in the purest and most vile sense of the term. He'd never stake his own personal safety on his so-called principles (Ironically, the only incarnation in which he ever showed that integrity was the "Age of Apocalypse"). The same is true of Dr. Doom, yes. But at least with Doom, well, his sacrifice negates the point of his quest. His entire stated purpose is "the world would be best off under the rule of Doom!" so if he were to sacrifice himself, how could he possibly carry out his goal. Whereas Magneto's end purpose is of Mutant supremacy, but the hidden feature is that he'll only fight for it so long as he maintains power.