Ah, but she didn’t commit a genocide, it wasn’t: “Kill all mutants”…
Manipulating reality is what Wanda does. Extricating what she considered as a curse from people when she was holding her dead brother killed by her father was her intention. She wanted no more sufferings, it was a cure.
Of course, the mutants didn’t share her opinion and were upset. But then, a good author would have shown, I think, mixed feelings about this: some mutants are very easy with their mutations and are proud of them, for others, it’s indeed a curse.