This reminds me of a mini head-canon I thought of once…. Basically my completely baseless nonsense theory is that grey, dull, mono-toned, simple or otherwise anything less than ULTRA vibrant and flashy is, or has been discriminated against in the past for their culture. Basically in a world full of multi-colored rainbow ponies, the more natural or “plain” looking among them are considered less special, maybe even some racism is in there. So basically the pony-world equivalent of gay pride, is gray pride.
Edited