I'll respond with some random thoughts of my own. If people were perfectly emotionless, there would be no exciting manias or frightening crashes, without fundamental data to cause them. We've all read about the public hysterias which lead up to wars and other unpleasant things. Public mood causes people to change their personal behavior. The summation of personal behavior is the public mood.
Economic activity is an aspect of the public mood.
The other link you make, between personal biochemistry and the longwave is not obvious. Biochemistry changes on an hourly basis, and the longwave occupies many years. Surely, with less serene surroundings, a higher percentage of people will display mood disorders. The guy who wrote it may be a mad bomber, but he has some significant insights into modern society. In my opinion.