Thinkers like Michel Foucault argue that modern institutions create forms of power that homogenize people by defining what is "normal" through disciplinary mechanisms and excluding those who do not conform.
Homogenization means individuals or societies losing their unique differences and being molded into a specific pattern, while sameness means everyone becoming alike as a result of reduced diversity.
Because sameness, homogenization, eliminates the ability to think alternatively; because sameness is monotony, it is soullessness.