Because cheesemakers add orange coloring during the cheesemaking process. It’s the result of hundreds of years of tradition, dating back to the time when cheddar cheese in England was made with milk from cows whose beta-carotene-rich diet produced an orange tint in the milk. Today, orange cheddar cheese is colored with annatto, the fruit of the achiote tree, while white cheddar is made without any added color.
I saw someone post a link to something like this the other day (maybe on Bluesky?) and I keep thinking about it lol never knew it was just added coloring.