In this line, Jackie Robinson is politely but firmly challenging President Eisenhower's suggestion that the Black community should be patient in their pursuit of equality and civil rights. Robinson is pointing out that the Black community has been incredibly patient for many years, enduring discrimination and injustice without resorting to violence or other extreme measures. He is suggesting that this patience has not been rewarded, and that the Black community can no longer afford to wait for change to come on its own.
Robinson uses syntax and diction to express his meaning in this line in several ways. First, he uses a parallel structure in the phrase "I respectfully remind you sir" to create a sense of formality and respect, even as he is challenging the President's views. This parallel structure also emphasizes the contrast between Robinson's polite tone and the strong message he is conveying.
In addition, Robinson uses the pronoun "we" to refer to the Black community and the phrase "most patient of all people" to emphasize the collective experiences and feelings of the Black community. This use of "we" and the superlative construction create a sense of unity and solidarity among Black Americans, and also highlight the fact that they have endured a great deal of suffering and oppression without resorting to drastic measures.
Finally, Robinson uses the word "again" in the phrase "not again" to express his frustration and resentment at the idea of continuing to wait patiently for change. This word suggests that the Black community has been waiting for change for a long time, and that they are fed up with being told to be patient. Overall, Robinson uses syntax and diction effectively to challenge President Eisenhower's views and express the frustration and impatience of the Black community.