If an orange is just called that because of its colour why wasn’t a lemon called a yellow?
The colour was named after the fruit. Before that, orange was just a shade of red.
Anyway, some very old languages have no word for blue, since the only thing they ever saw that was blue was the sky. And that was just sky coloured (we'd say azure, but they didn't bother with a word). Why have a word for a colour that you don't see in your life?
Yeah, I know, rainbows.
But one more thing, rainbows have only 6 colours. Religious numpty's made it 7 since that was more holy for some reason. There are only 2 strips of blue family. Indigo is made up trash. And kids keep learning Roy G Biv. Sad.