Question

As the chief executive of our nation, I respectfully suggest that you unwittingly crush the spirit of freedom in Negroes by constantly urging forbearance and give hope to those pro-segregation leaders like Governor Faubus who would take from us even those freedoms we now enjoy. Your own experience with Governor Faubus is proof enough that forbearance and not eventual integration is the goal the pro-segregation leaders seek. To which specific historic event is Jackie Robinson referring to in the letter? President Eisenhower’s argument over civil rights with Arkansas Governor Faubus at the Summit Meeting of Negro Leaders the day before this letter was written the riots of Harlem, which broke out in response to African Americans’ frustration at job discrimination, police brutality, poor treatment by the armed forces, and lack of access to economic opportunities Governor Faubus’s calling of the Arkansas National Guard to prevent nine African American students from entering Little Rock Central High School, despite the US Supreme Court’s ruling against segregation the rumored fatal shooting in August 1943 of a white soldier, which culminated in race rioting across the nation

Answer 1

the riots of Harlem, which broke out in response to African Americans’ frustration at job discrimination, police brutality, poor treatment by the armed forces, and lack of access to economic opportunities

Answer 2

The correct answer is riots of Harlem, which broke out in response to African Americans’ frustration at job discrimination, police brutality, poor treatment by the armed forces, and lack of access to economic opportunities.

There isn't much to explain here - black people thought they weren't represented properly in the American society, which is why they rebelled. There were many attempts to crush their rebellion which is obvious if you read Robinson's letter.