It's odd to me that you chose color as an example of something objective, since so much about perception is subjective.
Even if we think about it in more quantitative terms, with red being defined as having a dominant wavelength approximately 625–740 nanometres, it's a bit of an arbitrary definition isn't it? If we observe a wavelength of 624, objectively we might say it's not red, but someone may still observe it as red considering how close it is to red. Or someone with protanopia won't see anything in those bounds as red either.
Even if we think about it in more quantitative terms, with red being defined as having a dominant wavelength approximately 625–740 nanometres, it's a bit of an arbitrary definition isn't it? If we observe a wavelength of 624, objectively we might say it's not red, but someone may still observe it as red considering how close it is to red. Or someone with protanopia won't see anything in those bounds as red either.