It's also funny when people argue it's not actually white because color picker says it's light blue. Firstly, color motherfucking temperature.

It's because it seems like about half of people's eyes and brains correct it one way and the other half the other way, leading to extremely heated discussions about "how can you not see it my way." This isn't like other optical illusions like that silhouette of a spinning ballerina where you can easily flip it around in your mind. I've only ever seen this as white and gold once and it took someone putting it upside down and very slowly zooming out from a very specific area of the dress.

So that's why people were so torn about it.