Because blue color especially soft blue is the most convenient for eyes, a soft orange color even though wouldn't hurt our eyes, but it just not really convenient. Everytime I visit BPIP which has blue color origin, I never use other color since I doesn't feel good with it.
Maybe Theymos can somehow implement an orange one just for 1 day to see people and users reaction to that.
I think this can be an idea for the next April fools' day