I understand that. But if you think about it, each of the flag have meaning behind it, it isn't only to look pretty.
Pan has the three primary colors, (cyan, yellow, magenta) which create all colors-- pan=all
I really like the asexual and aromantic flags (i like them better separate than the aroace flag)
I like to think of them as easy color schemes. It is much easier to dress in black/white/gray with a pop of green or purple than it is to dress with three bright colors.