They are specified 'per segment' not per diode or whole device. The reason for specifying by segement and not diode is some (not that particular one) 7-segment displays use more than one diode per segment. Small displays are OK with one LED per segment but larger ones require more LEDs to evenly illuminate the segment area. Having said that, most displays with more then one LED have them wired in series so they need more voltage but the current may still be the same.
Brian.