Purple was sort of around. There was a dye derived by clams with a name that sounds like purple by the Phoenicians, Greeks, then Romans, and was more of a red-purple to red, but that eventually evolved into the word we use now. They also attributed it to the color of wine and of all things, the ocean.
Weirdly blue is a pretty rare color concept in the ancient world, and a number of cultures often just combined it with green, or vice versa. The closest to blue as a concept they usually got was indigo, another dye imported from India, and they’d dilute that into woad for a slightly lighter more pastel/ periwinkle blue (it wouldn’t stick as well as true indigo though).
I’ve found that people who don’t understand or enjoy media literacy or criticism also don’t tend to understand the concept of an analogy/allegory, and don’t want to either. Superman represents the “American Way” and can’t be an immigrant and the idea that America is a nation of immigrants is not relevant in any way. Only the old statements from Bridget from Guilty Gear count and not any of the new ones that confirm she’s trans. Naoto from Persona 4 and some similar stories like hers in other games can’t be a commentary on social pressures around restrictive gender roles, dysphoria, and performativity simply because she ultimately still identifies as a cis woman. You can explain the nuances until you’re out of breath, they will never accept the nuances.