I think that it is because the following reasons:
We have 6 abilities and each civ has 2 of them
so we have different 15 civs with not equal abilities
because 6 * 5 /2 = 15
6 random - 1 ability
and 5 others random - second ability
and now they doubled - because ofr example we can take first pick religious and second - commercial
and we can first pick commercial and then religious
so we have 15 different races with different abilities
and 16th race - japan doubles ability of other race
IMHO sid decide to give player all sets of abilities(couples of them)
so...
PS sorry for my bad english
We have 6 abilities and each civ has 2 of them
so we have different 15 civs with not equal abilities
because 6 * 5 /2 = 15
6 random - 1 ability
and 5 others random - second ability
and now they doubled - because ofr example we can take first pick religious and second - commercial
and we can first pick commercial and then religious
so we have 15 different races with different abilities
and 16th race - japan doubles ability of other race
IMHO sid decide to give player all sets of abilities(couples of them)
so...
PS sorry for my bad english