MLK had one famous line in a speech that has been leveraged by reactionaries to use him as a weapon against advocates of racial liberation. But that is not an honest use of his beliefs.
The whole movement for racial equality, and thus liberation, in the USA grew from intensely Christian foundations. One of the core tenets of abolitionism was the idea that humans are created equal, and such attributes as race or skin color are irrelevant before God, and hence to the faithful, too. Christ specifically said that being a Greek or being a Jew does not matter before God, and being a slave or being a master also does not matter; all are equal.
So, certain amounts of colorblindness are inherent to the very idea of people of different origins being equal, as it emerged in the USA, and supposedly elsewhere in the Christian-dominated areas of the world.
Also, it's the idea of equality, equal worth (before God), not of fairness or compensation; the latter might come from atonement and Christian love to the neighbor.
Eventually other ideas took hold and somehow eclipsed the initial ideas, not just of 1860s but also of MLK's.
I also think that Christians specifically should be comfortable with the concept of generational sin and personal sacrifice for social justice rather than a vigorous defense that one's achievement's are solely their own and must be hoarded at all costs.
This is a false choice. They are not the only two options.
Calling MLK's values "colorblindness" in the way of "racial liberation" is the kind of double-speak the GP criticizes. Language that distances everyone from the capital-T Truth that MLK knew and died for, in favor of small truths that pretend to unite but actually divide.