They don’t add nitrites to raw meat, only to processed one. Nitrites is why your ham is pink instead of gray. But, more importantly than color, nitrites are added as a preservative, to avoid botulism.
Wasn't the claim that nitrites help against botulism denied few years ago? According to Guardian: "A bombshell internal report written for the British meat industry reveals nitrites do not protect against botulism"[0]
Modified air packaging with carbon monoxide is _very_ common in the US. So the “artificial color” isn’t some dye or something… it’s how the myoglobin reacts to the MAP.