Some emergency controls (certainly fuel shut-off in a lot of types I deal with) are specifically coloured red, and on most aircraft red/green is used for indicating limitation exceedence - particularly in this context on engine gauges. This isn't comparable to traffic lights, since a traffic light has red-amber-green in different places, an indicator in an aircraft often doesn't.
The Americans have a wonderful system for pilots called I think a "demonstration of ability" which could be used to bypass a red-green colourblindness problem (in other words, prove you can spot any fault or exceedence in the sim), but to disregard it as having "no bearing on performance" seems a bit foolhardy to me.
G