I think I have an explanation..... maybe they got a deal on red and black ink and toner for there printers.
A red–black tree is a type of self-balancing binary search tree, a data structure used in computer science. History[edit]The original data structure was invented in 1972 by Rudolf Bayer[2] and named "symmetric binary B-tree," but acquired its modern name in a paper in 1978 by Leonidas J. Guibas and Robert Sedgewick entitled "A Dichromatic Framework for Balanced Trees".[3]The color "red" was chosen for the name because it was the best-looking color produced by the color laser printer available to the authors while working at Xerox PARC.[4]