I think that's a stretch. I don't think the ancient Canaanites viewed Moloch as evil. Even Milton and Flaubert consider him a god. I think such definitions only make sense within the context of the religion. I could argue that Yaweh is a demon because he is evil (has also asked for child sacrifice among other things), but that is an absurd claim within the religion where by definition he is good and the source of morality.
So by calling Moloch a demon, you are participating in perpetuating a potentially false history of Moloch that is heavily biased and Judeocentric. Sure you can call him an evil pagan god, but to call him a demon requires fitting that into a prior belief system of evil supernatural entities which is inconsistent with the very belief system he came from.