Sure, I think it's justified for Autocracy as it's the domination ideology and should benefit from increased army size. The fact that it has so much of them though is caused by the general abundance of supply at the late-game, at least in my opinion. They need so much because their rivals already have too much, and Autocracy civs are likely to fight at multiple fronts. If the community ever decides to reduce the late-game supply, Autocracy may not need so many supply bonuses too.