I disagree about insertions and deletions. The primary purpose of colors should be to communicate more information without us having to think about. Having standard color schemes is really helpful. If every service uses different insertion/deletion colors, that's just more headache for us.
Additionally, to me, red deletion doesn't mean "this was a bad action". It means "this was bad code, so we're crossing it out". Semantically, that makes total sense to me. Red is bad old code, green is new good code. Seeing a lot of red in code means the same to me as seeing a lot of red on a marked up copy of an essay (as long as it wasn't a professor who marked it up) -- I've identified a lot of improvements to make.
Additionally, to me, red deletion doesn't mean "this was a bad action". It means "this was bad code, so we're crossing it out". Semantically, that makes total sense to me. Red is bad old code, green is new good code. Seeing a lot of red in code means the same to me as seeing a lot of red on a marked up copy of an essay (as long as it wasn't a professor who marked it up) -- I've identified a lot of improvements to make.