A big part of the criteria for selecting the 50 "dumbest" people in Hollywood was stupid life choices and bad career moves. No matter how shy or inarticulate both Andy Garcia and Robert Deniro may be, neither of them seems to have committed unrecoverable blunders in choosing their work, or living their lives.
Based on that criteria, it is easy to see how "Lilo" rocketed to the top of the dum-dum list, with a succession of bad life choices, and dreadful careers moves.