Sega is also Japanese. I'm not sure what you're trying to prove anymore.
Colors should have meaning. They should help you to identify and remember buttons. A color should always stick to the same button. If you change the order of buttons, the colors should move with them. Button A should always be the Red one, on any controller by any company.
Color symbolism and psychology should be used in games. Blue could mean flying or swimming, Red obviously is firing and Yellow could be gold or light. Every PC gamer knows, R is Reload and G is Granades in almost every game. And those buttons don't move on your keyboard. They stay where they are and they don't swap colors to confuse you.
The only thing all game controllers have in common is that one button is to the left and one to the right of your thumb. One is up and one is down, but what color it has is absolutely arbitrary. And the letters are ordered by the latin alphabet, so depending on reading direction they are always backwards somewhere in the world.
Only the Playstation buttons don't need to have that problem, because there is no implicit order to geometric shapes.
But they have it as well, because the rest of the console industry has it.
You assume it's supposed to?
No, they are not supposed to, but matching your companies brand at least gives some kind of reasoning, why one color is here and one color is there. And since button coloring seams to be highly company specific, stick with whatever color brand your company already has established.
This way we can at least replay all of the 18 games released for the
Apple Bandai Pippin on our iOS devices with the "right" apple colors.