If the drug was available, I think that it should be used very cautiously, and only with those individuals where their shyness negatively impacts on their lives.
It would be ideal if Phoenix's statement could be the standard instead of sales quotas and the bottom line.
There are too many instances and extremes for there to be one answer. There sould be plenty of room for introverts and extroverts in our society, but when a characteristic is so extreme that it affects one's life, then drugs can be useful, even life saving. Remember, depression can easily become a terminal illness without treatment, more often than not with drugs.
Modern drugs have saved many lives and they shouldn't be demonized just because too many people use them for less than serious reasons.
IMO, it becomes morally repugnent when drugs are used on children to calm their behavior rather than dealing with it with proper medical supervision. This would include drugs, if they were subscribed and supervised by a doctor instead of the teacher and used only as a last resort.