I do not lionize the Kennedys in this essay. Quite the contrary, I list JFK as one of the pretenders, one of the many "white liberal" leaders who made noises about "social justice" and "civil rights" while fully accepting the status quo in the Jim Crow segregated South up until, just as you say, that position became untenable and an embarassment for them -- and America generally.
No. The reason black people still revere the Kennedys is because when Dr. King was jailed and his life was seriously threatened during one of his many marches (Birmingham), JFK and RFK actually and publicly called King's wife to console her and "express" support for him.
Also, JFK did at least propose the Civil Rights bills that he never got to enact. Indeed, I have more respect for LBJ than any of the Kennedys.
Thanks for responding/reading.