Today is a national holiday honouring Martin Luther King, Jr., the great non-violent civil rights leader of the 1960s. Because of his efforts and the efforts of hundreds of thousands - maybe millions - of USAers, laws enforcing and perpetuating segregation, the USA's apartheid system, were outlawed and racial equality became the law of the land. This was very good.
I do feel the need to point out that passing laws is one thing and getting them enforced is another. [Think of India's anti-dowry laws, for example] The enforcement actually involved quite a bit of violence on both sides. Things seem to have settled down. The election and presidency of Barack Obama is one indication of this.
About the video:
For those who may not know, "Abraham" is Abraham Lincoln, sixteenth President of the USA, who is credited with freeing the slaves;
"John" is John Kennedy, 35th President of the USA;
"Martin" is Martin Luther King, Jr.;
"Bobby" is Robert Kennedy, JFK's younger brother who was running (standing) for President in 1968.
All four were assassinated.