When you're camping on top of some wall taking pot shots at enemies you're not being very valourous. The most effective archers are the ones closely following the melee mob and taking close shots, which really help us melee-ers, as well as protecting our flanks and rear from cav. I'm not sure how close you have to be to the combat to get residual points, but the closer you are the better chance you have of hitting the enemy rather than your ally.
Melee gets valour because when you get close to the enemy its pretty easy to get separated from the main mass and get swarmed. If an archer is in close support he also has a chance of getting surrounded and dying right away, but that's where you need to be a little brave and take the risk.
And yeah, I don't mind friendly fire when I'm surrounded and about to die. But I really hate it when there's 6 guys trying to finish off a lone enemy and some archer feels the need to try get the point by shooting halfway across the map for a few more points.