Final answer:
The major cause of the 1960s riots was frustration and anger resulting from the lack of essential resources in urban African American neighborhoods, as stated by the National Commission on Civil Disorders.
Step-by-step explanation:
The major cause of the 1960s riots, as stated by the National Commission on Civil Disorders, was frustration and anger resulting from the lack of healthcare, job opportunities, and safe housing in urban African American neighborhoods.
Despite the programs of the Great Society, these essential resources were severely lacking, leading to disillusionment among African Americans.
The federal government and existing civil rights groups were seen as unable to bring about significant change, causing many African Americans to embrace more radical ideas for achieving racial justice and equality.