The author is suggesting that many people at the time did not take the Nazis seriously enough. Instead of recognizing the true danger of their ideology and actions, people often dismissed them as a fringe group of obnoxious and repulsive individuals. This failure to take the Nazis seriously allowed them to gain power and influence, ultimately leading to the atrocities of World War II. The author is pointing out that it is important to recognize the true danger of extremist groups, even if they seem ridiculous or absurd on the surface. By taking them seriously and opposing them early on, we can prevent them from gaining the influence and power that can lead to catastrophic consequences.