Those riots were mainly 1965-68. Up through 1964, I would say the civil rights movement was pretty much a righteous cause. But starting in 1965, and increasingly thereafter, not so much. The significant gains had been achieved, and things started to go downhill. The more "militant" leaders began to come to the fore. LBJ's Great Society began to destroy the black community. Then in 1968, after the King assassination, there were lots of riots.
(BTW, I date 1965 as the start of the decline of the American culture.)
(BTW, I date 1965 as the start of the decline of the American culture. Although my date for the start of the decline of American culture is November 8, 1960, when JFK was elected, one can make a powerful argument for 1965.