Thomas Jefferson could be called a hypocrite for owning slaves precisely because he opposed slavery in principle. His ideas are worth honoring. MLK embraced socialism and opposed private property rights in principle. His ideas were largely not even his own (his famous "Dream" speech also contained plagiarized material).
Murray N. Rothbard put it well: "Scratch an egalitarian, and you will inevitably find a statist...
"... flying in the face of their former supposed devotion to the absolute rights of private property, the libertarian movement has embraced almost every phony and left-wing "right" that has been manufactured in recent decades.
"...I told two well-known leaders of the movement that I thought it had become infected with and permeated by egalitarianism...Further, I said that a good indication of this infection was a new-found admiration for the Reverend "Doctor" Martin Luther King. Absurd, they said. Well, interestingly enough, six months later, both of these gentlemen published articles hailing "Dr." King as a "great libertarian." To call this socialist, egalitarian, coercive integrationist, and vicious opponent of private-property rights, a someone who, to boot, was long under close Communist Party control, to call that person a "great libertarian," is only one clear signal of how far the movement has decayed.
"...there is one excellent litmus test which can set up a clear dividing line between genuine conservatives and neoconservatives, and between paleolibertarians and what we can now call "left-libertarians." And that test is where one stands on "Doctor" King...
"...Throughout the Official Libertarian Movement, "civil rights" has been embraced without question, completely overriding the genuine rights of private property...
"...Part of 'social tolerance,' of course, is uncritical and unlimited devotion to open borders; as in the case of most left liberals and all neocons, any proposal for any reason to restrict immigration or even to curb the flow of illegals, is automatically and hysterically denounced as racist, fascist, sexist, heterosexist, xenophobic, and the rest of the panoply of smear terms that lie close to hand."
Lew Rockwell And The Strange Death (Or At Least Suspended Animation) Of Paleolibertarianism