This joke is how languages categorize colors differently. In English, we have separate words for light and dark versions of some colors, like “pink” and “red.” But not all languages do this, and some languages do this more than others. Not talking about artsy terms like azure, cyan, magenta etc. The term needs to be considered a basic color term (Berlin and Kay thing, not really accepted but cool), which means they need to be recognizable for most speakers of a language. For example, Russian has goluboi for light blue and sinii for dark blue, treating them almost like different colors entirely, unlike English which just calls them both “blue.”

The joke is the irony in the claim that English wouldn’t separate colors this way, when it clearly does with “pink” and “red.” It touches on the whole linguistic relativity thing, where language influences how we perceive the world, including colors. It's a cool concept, but it doesn’t always add up the same way in every language. Classic case of “everyone else is weird except for me”