The Batlord

If I'm a human then mutants are clearly a threat to be neutralized. Many is the time (e.g. Proteus, Phoenix, Magneto, etc) that an omega level mutant has proven that they could very well cause destruction on a level that's at least as horrific as an atomic bomb, except the atomic bomb is in the hands of an often teenage or early 20s person with the massive existential crisis of suddenly being a "freak" to make them too unstable to reasonably contain. What could you possibly do but kill them all? X-Men makes us question this solution simply because it is a comic book and deals in elevated comic book morals no matter how much it tries to be realistic, but truthfully they are a time bomb, and there's no telling if a mutant might come into existence whose power is simply to blow up the Earth. Kill them.

Of course if I'm a mutant I'm not about to sit down and be murdered by Sentinels, and humanity's penchant for genocide against people with far far far far far less differences and supposed threat levels than even mid-level mutants makes it clear that they simply can not be trusted to accept mutants out of the kindness of their hearts. They will kill you. No words or deeds you can muster will stop the genocide so you might as well side with Magneto because Professor X is delusional in the extreme.

Although there's also the issue that "normal" mutants would still be subject to omega level mutants they'd be unable to contain (especially since this wouldn't be a comic book and there'd be very little assurance that the X-Men could win against every single threat that could potentially wipe out all human or mutant life) so even mutants would be unable to escape the necessity to murder certain members of their kind, potentially to the point that they'd be forced to look for a cure simply to avoid extinction.

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