Read what I wrote again. I’m not disagreeing with avoiding those colors. I’m disagreeing with the bit about never having an issue by just avoiding those colors.
I’m confused why it would be a problem if you use other colors though. If you use something like purple then I don’t see how you would get into a situation where something goes awry due to your color (Assuming your code is consistent)
Let’s say you use purple lights and you have them flash when the robot has loaded a ball or is on target to fire. Or maybe you have purple and magenta lights to indicate which autonomous mode you’re in. The latter case has been explicitly ruled a functional use of the LEDs, and the former is even more functional and so surely would be. So just because you’re using purple lights doesn’t mean your use of the lights is considered non-functional decoration.