Warfare is not a physical mod, Warfare is the warrior skill tree, the same as pyro is the pyromancer skill tree and scoundrel is the rogue skill tree.
Hunter, Scoundrel and Necro are all physical classes as well.
The fact that the warrior skill tree gives a better bonus to an archer would be the same as if pyro skill tree would increase damage for all mage schools instead of only to pyro.
and yet warfare along with skill tree increase physical damage. much like pyro along with skill tree increase fire damage.
that's why they are similar in their design. and skills are irrelevant in this case.
