Why is it the Aztecs are the only civilization to be missing the Galleon?

Seeing as the Aztecs are already not a great water civilization due to the lack of Cannon Galleons and the lack of Demolition Ships (only getting the Demo Raft), it seems a bit much that they also don't get Galleons. Is it a conscious design decision to not let them have it, or is it just meant to be for historical reasons?

Even though they get Shipwright, that does not make up for lacking the Galleon upgrade, since War Galleys are much weaker (less HP, attack, armor, and less bonus damage).