Dichromatism is a disorder. Our brains expect a trichromatic signal and when it only receives dichromatic information the hues are “repeated” because a cone (usually the one responsible for green) is not available. In people with green-weak color blindness this makes green look like a “weak” reddish hue. Tetrachromats’ brains are still expecting a trichromatic signal but they get more information than is expected. That means that the image contains more information or detail but the colors are not nee colors.
That’s not how brains or vision work. The brain is not “hard-coded” for trichromatism. Were that the case we would not be trichromats in the first place.
Our brains are rather complicated, interesting things- and probably do something like wire themselves up to whatever "sensors" are available.
What if trichromatism is also a disorder, that afflicts the vast majority of humans?