That's pure nonsense. I don't think anyone is fooled into thinking that MLK said those exact words, just as they aren't fooled into thinking that MLK was sitting in the Dunder Mifflin office.
With that said, MLK did say, ""I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character."
This meme is a play on that message but directed at the ugly anti-white racism that is growing in our time. It is a great meme.
Eh? Why is it it "invalid"? Of course it's a valid point; you just disagree with it. If a meme is invalid because the person in the picture "never agreed to" the point, then *all* memes would be invalid.
After all, I don't know if John Krasinski has ever agreed to a single point made in any meme with his picture in it.