He was an evil pr*ck to do what he did and that truly is black and white to me.
Johnny Depp, I think, was arguing that, because not everything Mr. Bulger did was evil, then we can't say, "He was an evil person." I think Depp is wrong. A certain level of evil action makes for an evil person, even if some of his actions - eating his meals - are morally neutral and some - kindness to a pet, perhaps - may be virtuous.
Mr. Jacoby, the author, would agree with this, I think. His point was that Bulger chose to do the evil acts and had the capacity to have chosen not to do them.
excellent analysis there... you are spot on.