"Alice is in Denver. Is Alice in (a) Canada or (b) Mexico?"
- Your boundary between Canada and Mexico is at 40° latitude, more southern than 53% of the population.Rather than asking "Is this blue or green?", it's "Does this look more blue to you, or more green to you?"
Because then your analogy becomes "Is Alice closer to Canada or Mexico?"
Denver is teal, the USA blue-green. Canada is Blue, and Mexico is green.
Their analogy is pretty on point.
Countries are not a continuum, they start and end at some specific line defined by constitutions, mutually agreed by neighbours (or disputed through war and diplomacy) Colours have no such incentive for strict unified definitions, so there is no point at which blue ends.
You're inability to wrap your head around the analogy is tantamount to.. Not being able to comprehend blue-green.