Emotions are the state indicators of the Human Motivation Array (HMA). The degree of satisfaction of the HMA of an individual is indicated by the face and voice and movements of that individual. In complex social interactions (civil society) it is essential that we be able to quickly and accurately assess the state of the person"s HMA that we are interacting with in order to adjust our own behavior. I believe the male facial hair is not a sex indicator but meant to obfuscate the state of one's HMA, to hide it from other males. We must not, in evolutionary time, show fear or anxiety before other males. We take that beard off in complex societies to communicate more effectively, not for hygiene reasons. Women have no facial hair because their internal state must be read more accurately both by other females and by males. We know females have greater communication needs and skills. Their emotional state, and therefore the state of their motivation array is more clearly expressed to those who can read them. And human females have no trouble identifying and mating with a human male with no beard. It can't be much of a male identifier. More primitive societies still retain beards because there is more male to male fear in their beliefs.
This is why a Vulcan society based on the suppression of emotion is not possible. They would have no idea if that Vulcan opposite them is about to kill them or cooperate with them. They simply would not be able to read each other.