When Batman tries to argue that he should lead the Justice League, he says that Green Lantern can't lead because:
Your weakness is the color yellow. [...] If you're going to stop a mugging and the guy's wearing all yellow, what're you going to do?
Out of universe, I assume yellow was chosen as the weakness of Green Lanterns because:
Green Lanterns are powered by imagination as much as they are by will, and a weakness was necessary to prevent them from being unstoppable.
Yellow is among the colors most associated with fear, so it's a logical connection
What is the in-universe reason why Green Lanterns have that weakness? Did the Guardians of the Universe install it as a fail-safe in the event of a rogue lantern? Is there a physical and/or chemical component of the color yellow that directly prevents Green Lantern rings from acting upon it?