I think they might be. blue would've been a better choice. it's weird that people still use red and green when it's the best known and most common form of color blindness and it affects as much as 1 in 20 people, give or take. that's not a small percentage. color blindness in general affects 1 in 12 people.
that's for red-green, which is why I said about 1 in 20 -- maybe closer to 1 in 25 -- but in total, all color vision deficiency types add up to around 1 in 12 people.
There is general agreement that worldwide 8% of men and 0.5% of women have a red/green type of colour vision deficiency.
[...]
The 8% of colour blind men with inherited colour blindness can be divided approximately into 1% deuteranopes, 1% protanopes, 1% protanomalous and 5% deuteranomalous
the thing here is even 8% is the total number of CVD men, that's inherited. there's also CVD that comes with age:
... as many as 3% of the population could be affected because age-related deficiency is relatively common in the over 65s and therefore on the increase in the UK due to the rising numbers of elderly people per capita
so that's more people. added to the 4.25% that would make 7.25% -- somewhere between 1 in 13 to 14 people. doesn't matter too much, it is significant and should be considered in design.