In this article, the author talks about the definition of the term herd behaviour when it applies to humans. This is a behaviour that people sometimes adopt and which leads them to act in irrational ways or with panic. When people follow this behaviour, they act in the way in which they perceive the crowd to act, even when this is not beneficial or logical.
Paragraph 7 provides an example of this type of thinking in action. In this paragraph, we learn of the way in which Hitler used this tendency to gain support for his cause. By providing this example, paragraph 7 allows the reader to think of what the behaviour looks like in action. It also allows the reader to better appreciate the consequences of herd behaviour in real life.