How would you feel about a test for "teal or blue" or "teal or green?" You still need to make binary choices, just along different boundaries. Would it make any difference?
if the question was "is this more blue or more green" it would be somewhat more agreeable. but there really just have to be a "can't decide" option as well.
If you gave me the exact same color code 20 times I might give you green 10 times and blue the other 10 because I genuinely can't tell the difference. So it's not a binary like you're claiming.