We have more than just statistical evidence. We have physiological evidence too. We know which kind of protein (opsin) is responsible for each wavelenght. We know what kind of genetic modification can change the protein substantially (if you change the Nth protide which is hydrophilic by an hydrophobic one, you can change the wavelenght perceived). This is exactly my point:

You have an observation: Dichromacy is more prevalent with men, tetrachromacy only ever appears with women. This prevalence is huge. Opsins are responsible for colour perceptions

You have a theory: the X gene is responsible for colour perception: the L and M opsin are encoded on the X gene. You found the responsible gene.

Again, his is exactly my point: no physiological evidence => garbage bin (unless you're a researcher).