Understandable. With all this great buzz surrounding Abrams and the new movies, the last thing they want to do is remind people again of the prequels.
The prequels were hugely successful and judging by review aggregate websites were well enough received. The idea that the general public hate them is a total myth. Revenge of the Sith was one of the highest grossing films of that decade. It wouldn't have been if everybody hated the previous 2 movies.