Final answer:
LH Morgan's work was discredited due to its ethnocentric perspective and outdated unilinear evolutionary theory, which oversimplified human societies.
Step-by-step explanation:
The work of Lewis Henry Morgan, an American anthropologist, was eventually criticized and discredited in the field due to its ethnocentric views and obsolete theories. Morgan's unilinear evolutionism, which categorized societies from 'savage' to 'civilized', reflected a biased and unfounded understanding of human development. His comparative method, which sought to classify and arrange societies into stages of development, and his theories of kinship and social structure faced substantial criticism for oversimplifying the complexities of human societies. As anthropological methods advanced, Morgan's work was thrown out for being too speculative and no longer being representative of the diverse and non-linear ways in which societies evolve and operate.