Does Genesis talk about a Serpent or a Diviner, as in a Divener of Knowledge?
What is so wrong about knowing the difference between good and evil? Well, it depends on one's perspective. From the perspective of the slave master, when slaves know the difference between good and evil, then they are more difficult to control and take advantage of.
Of course, slaves would like to have this knowledge so they can free themselves from the slave master and exercise their own Free Will.
Kind of like Q/Q+, et al. are Diviners of Knowledge who seek to free the slaves.