Moral realism is strangest thing my colleagues widely believe. It's like everyone around me is sensible, sober minded, and believes that fairies steal milk on the window sill and consider it bizarre when one thinks we really ought look for some other explanation for missing milk.
The negative arguments in this aren't all that great but its good for building up a positive alternate picture https://www.amazon.com/Ethics-Inventing-J-L-Mackie/dp/0140135588 …