fighting rangers

In sector 8 ,according to the combat guide ya use nothing but recruits. Im wondering,if rangers are ranged troops why wouldnt ya use bowman or longbowman to take them out? This doesnt make sense to me. Why wouldnt you use ranged troops against ranged troops?

Because you don't use costly units with low hitpoints against units that delivers high damage. You use expendable units with relatively high hitpoints.