Answer: realities of economic disparity became more apparent
Explanation:
When it became more glaringly obvious to people that the economic disparity between the blacks and the whites was quite much because the system was built on the foundation of oppressing some groups and keeping them poor and disenfranchised, more people in the civil rights movement became radicalized.
Up till then, they had believed that civil rights could be won legally and nonviolently became the system could be changed but after the disparity was noticed, a lot of people began calling for the system to be revamped entirely.
To historical examples are given which is super important in the question!
