Final answer:
Whiteness was perceived as a threat and out of the norm due to historical roots of tension between laws and norms, different definitions of White racial identity, and the existence of White privilege and supremacy that perpetuate inequalities.
Step-by-step explanation:
Whiteness was perceived as a threat and out of the norm due to a combination of social, political, economic, and cultural factors. One reason could be the historical roots of tension between laws and norms in society, where laws denied many African Americans the ability to achieve full equality. Another reason is the concept of White racial identity and how it has been defined differently throughout US history. Additionally, the idea of White privilege and White supremacy perpetuate inequalities and create a wide gap between white, middle-class Americans and other groups.