I agree with Scottish.CPL except for the last 4 words ..... "because it's fair".
IMHO the OCVT and MFT would be "fair" only if they tested whether we can perform the required task of safely flying an aircraft and do not ask us to name the colours. We don't always get that right.
After all - naming colours is not a task a pilot has to perform [except in medical tests].
Does anyone here actually think you need good colour vision to fly an airplane?