CW: Pretty graphic

I'm reading "The Phoenix Program" by Douglas Valentine right now, and the author has mentioned the brutality of the Viet Cong, in morbid detail (in one section he mentions a pregnant woman having a fetus cut out of her and put on display in a village). This is only really glossed over, since it is beyond the scope of the book. I'm wondering if there is a book or something detailing the history of the VC that I might check out that isn't packed with lies. I'm specifically wondering why they chose to use "terror" against civilians so frequently as well as who they were hitting exactly. I'm also wondering if they made any measurable difference compared to the North Vietnamese Army. Any complete histories that I might check out?