The reason is this: Lumileds sells Cyan luxeons for traffic light manufactures. If you've noticed traffic lights aren't true green or yellow-green. The reason is for color blind people, so they make them that emerald green. So lumileds on purpose makes their cyan this emerald green for traffic lights since traffic lights wouldn't use their straight green.
Keep in mind your eye can make out LOTS of "tints" of green, more than other colors, so there is a lot of variations you can make out.
To get a REAL cyan color, you need ~480nm (argon laser color). You need a bin 1 cyan and drive it HARD. A luxeon1 overdriven will shift more bluer too that's why PSM's Q2H luxeon one overdriven to 800ma looks better.
So yes they are typically greenies. I searched hard to get my cyan that was really cyan and not made for traffic lights