Individuals Act

"A king may move a man. A father may claim a son. But even if the men who move you be kings or men of great power, your soul is in your keeping alone. When you stand before God you cannot say, 'But I was told to do thus,' or that 'Virtue was not convenient at the time.' That will not suffice. Remember that."
--King Baldwin IV (Kingdom of Heaven)

Axiomatically, only individuals act. Groups, races, classes, nations etc exist but they can only act through individuals.

For example, Japan attacked Pearl Harbor on December 7, 1941, but only because certain individuals flew airplanes and dropped bombs on US ships. The US declared war on Japan on December 8, 1941, but only because certain individuals in Congress voted to declare war.

Yes, social pressure can persuade action. And herding tendencies can drive like-minded behavior.

But this does not alter the truth that when analyzing human action, the core unit of analysis is the individual.