The correct answer to this open question is the following.
What Martin Luther King meant by saying that “let us not speak our thirst for freedom by drinking from the cup of hate,” was that the civil rights movement that he led, was never going to use violence as a form of protest or demonstration. Martin Luther King wanted to express dignity for other people and respect for other forms of thinking. That was part of his line of conduct, and for Dr. King, this represented great value and separate him from other activists that used violence, as was the case of Malcolm X.
What would MLK say about this today if he were alive?
Exactly the same. As we have seen in recent and pitful events in many places of the United States, racial segregation and racial violence are still very active in America. The use of non-violence would be his "flag" despite the terrible aggressions suffered by African Americans.
