All right. This one is tremendously difficult.
Mainly because the movie was crap and nobody liked it, except me of course...
Hint A: "The library is closed. All white people must leave"
Hint B: "What difference does it make? What difference does it make?"
Hint C: "You're all doomed"

-and the movie is?
The right answer is:
This is the crap movie Hysterical from the year 1983
The geniuses that had the right answere were:
• Zelig:
"Júmm, myndin var slöpp og með leikara innanborðs eins og járnkjaftinn
Richard Kiel og Disney karlinn Keenan Wynn, það segir allt. En ég hló nú
samt eitthvað enda í upphafi unglingsáranna."
• Jack Nicholson:
"This is the movie Hysterical, and I say this in the firm belief that you will not post this on your page. I simply love this movie. The only movie I have watched over tvo hundred times."