This is directly addressed by the ANSI/TIA/EIA 568-B Commercial Building Telecommunications Cabling Standard:
Connecting Hardware and Polarity
Optical fiber shall be installed with odd numbered fibers having
Position A at one end and Position B at the other. Even numbered
fibers will have position A and B reversed from the odd numbered
fibers. When using the 568SC connector or other duplex connectors, the
above polarity must be maintained.
When using copper cabling, it must be straight through from termination to termination, but optical cabling must be cross from one termination to another.
The reason fiber cabling is crossed is simple: when connecting fiber from one device to another, the fiber strands need to be cross so that Tx goes to Rx on each end. For this reason, fiber patch cables are crossed, but when you have horizontal cabling, you have two fiber patch cords which cancel each other out. When the horizontal cabling is crossed, you end up with three crossed cables, making the whole a crossed cable, leading to success.