the cultural association makes it easier to parse- a red diff is clearly very good because lots of bad code (red) is being removed (red) if your boss looks at

the cultural association makes it easier to parse- a red diff is clearly very good because lots of bad code (red) is being removed (red) if your boss looks at a red diff and thinks it's bad, that's a you and him problem, while the primary purpose for color syntax continues to be making it easier to parse for people who know what they're looking at