For new players coming into the game, it might be a good idea to include some text in there indicating why they are evil or what type of evil acts are required or even typically required for the transformation into a lich. Right now other than being spooky there isn't really anything called out in the Bestiary entry that sounds intrinsically evil. Not even the insert the soul into an item, since there are other examples of not-intrinsically evil ways of putting a soul into an item.
I've looked up the 2nd edition entry on liches and it had some extra lines explaining the evil things required to become a lich. Not all players have that background and as such it shouldn't be surprising to see people asking "why exactly is this evil based on the information provided." Without rationale for something being good or evil, the labels become substitutable with Team Green and Team Purple.