Emma Frost, how quickly I forgot Mrs. Frost, yes, she's killed too, for money, power, or just whim..., she changed, who knows, maybe Arclight or Scalphunter could change, but it wouldn't mean they would/should be free of consequences for what they did.
The state of the U.S. govt towards mutants has little to do with justice, nor does the typical citizen have much sympathy for mutant life. Kitty Pryde remarked that most people thought the Genoshan Mutants "Got what they deserved"( X-Men Unlimited #36/1), and the "Muties" title is full of people killing mutants with no consequence (From America to Africa to Ireland to Japan, so it's not just the U.S.), it's open season on mutants.
When I get hyped-up I don't think, I run purely on emotion, if they turned over Arclight and Scalphunter to the police, they'd be dead before reaching jail, or the police would...Also, as I said, I need to be more aware of the line between fantasy and reality, and not to stress over the bad things that happen in fiction, when I have enough stress from real life...
Banshee said, regarding Donald Pierce: "He's a cyborg with a madman's hatred for mutants. To him, the only good mutant is a dead mutant." to which the Cheyenne Forge replied. "My ancestors knew the type..." Uncanny X-Men #262.
When that "Type" gain power, whatever idea they represent, the results are very, very ugly...