The irony is that the commercial uses a speech that literally criticizes car commercials for tricking people into buying shit they don't need:
Now the presence of this instinct explains why we are so often taken by advertisers. You know, those gentlemen of massive verbal persuasion. And they have a way of saying things to you that kind of gets you into buying. In order to be a man of distinction, you must drink this whiskey. In order to make your neighbors envious, you must drive this type of car.
But now the problem is, it is the drum major instinct. And you know, you see people over and over again with the drum major instinct taking them over. And they just live their lives trying to outdo the Joneses. (Amen) They got to get this coat because this particular coat is a little better and a little better-looking than Mary's coat. And I got to drive this car because it's something about this car that makes my car a little better than my neighbor's car.
There is a whole trope about people turning MLK into a bland symbol of racial progress, when he was both a socialist and way more confrontational than people seem to want to think. Which makes sense, given that we've turned him into a saint where criticism is proof of racism, so the reaction to twist the message into something benign is pretty predictable.
Sort of like when the Janis Joplin song was used in a Mercedes commercial, or when politicians use "Born in the USA" in a jingoistic context, but somehow way worse because it is a whole persona and legacy being twisted instead of one isolated communication.