>They are consequential to the population as a whole, not just a segment of it.<
I respectfully disagree with the statement that MLK was only consequential to a segment of the population. As a native Virginian, from where I sit MLK was most certainly consequential to the nation as a whole, as he embodied the victory over segregation. King was the focal point of the Civil Rights movement.
Segregation might not have been nationwide, but it was a cancer to the entire body of the United States. The evil of segregation had to be excised, for our nation to grow.
I remember when local black people could not freely go to a public swimming pool, or to a restaurant, or even to a given restroom. That our laws allowed such prohibitions is in direct contradiction to the idea that "all men are created equal".
Now, I'm not convinced we needed yet another federal holiday, but I am convinced that MLK is and will remain an important historical figure to every citizen of the United States.
But you could make that argument about many people who fought for the interests of their own group. That's my point. I.e,
Cesar Chavez helped end exploitation of Mexican migrant workers, which, though it didn't happen everywhere, was a cancer on the entire country.
Brigham Young led the Mormons when they were "segregated" by violence against them because of their religious beliefs. This only happened in Missouri and Illinois, but in a country founded on freedom of religion, this was a cancer on the entire country.
Every group has its heroes.
And King didn't end segregation. Brown v. Board of Education, ending school segregation, came down in 1954, while King was still an obscure preacher. This was a movement that was well under way before King gained prominence.
King probably did influence the passage of the Civil Rights Act of 1964 -- which was supported mostly by Republicans, by the way. One can argue whether that law has made the country more fair or less fair. While the ending of segregation was supposed to unite us all, regardless of race, the things that came after, promoted by King, have tended to divide us by race, bestowing special privileges, protections, and preferences on certain groups, subjecting employers to endless ridiculous lawsuits brought by bad employees who happen to fall into particular groups, making it impossible for employers to set standards for their workplace -- like making a high school diploma a minimum requirement -- because that "discriminates" against certain groups, etc., etc., etc.
My sense is that, before King rose to prominence, the majority of Americans, out of a sense of fairness, were already moving toward a color blind society.
Think about it. America had been steadily moving in that direction since its founding. Slavery, for example. Slavery had existed in the world since the beginning of time. Powerful groups routinely enslaved weaker groups.
In the nineteenth century, for the first time in recorded group, Europeans and Americans said, "We are strong enough to enslave others, but it is wrong, and we are not going to do it." Then, they forced the rest of the world to do it, with certain holdouts in parts of the Middle East and Africa. Slavery was legal in Saudia Arabia until 1916 or 1917, I believe.
Much of the stuff that came out of the "civil rights movement" led by King and other has led us in the opposite direction, and has set back the cause of individual rights and "color blindness," in favor of group rights and preferences. These group rights, in my opinion, have created as much or more unfairness as they have prevented.