Jacobstown-
Not just the mercenaries that were hired by the NCR to antagonize and then kill the supermutants there but there very existance. Why would they move away from Gecko unless the NCR pushed them away?
Mean Sonofa[censored]-
A supermutant who was captured by the NCR in the Hub, held prisoner and tortured by them. His tongue was cut off by them and (apparently) the public knew about him because Klamath Bob tried to buy the poor supermutant's freedom. He wasn't freed until Tabitha and her supermutants rescued him.
How can so many people overlook this could hard evidense! They hate peaceful supermutants, and yet people still see them as white knights (just like Lyons' BoS, which is racist against ghouls).