I was creeped out by the scene as a child, but I thought it wasn't the Raptor talking. I thought, instead, that the Raptor made some sort of sound (that was the 'jump-scare' OST of the sequence), and then Billy's voice came from over the dream. When I re-watched the film and noticed how it really is, I changed opinion on it, but it's not really somethign down-grading.
Come on guys, let's remember the scene was a dream. Incredible things can happen in dreams. Perhaps the intention was to show Grant's fear that Raptors may take their intelligence too far, and that is not 'expressed' in a logical way in this dream.