Spoiler territory!!!

I mean, the game isn't explicit with gore or anything like that for sure, but I don't see what isn't vicious about a toddler drowning to death as the result of absurd parental neglect, a 10 year old being neglected to the point of death by unintentional poisoning and starvation (locking a child in their room without dinner seems a little harsh maybe), a mentally unstable 21 year old being killed by decapitation, an 11 year old dying because his family figured there was nothing that could possibly go wrong putting a swing on the edge of a precipice over the ocean, Barbara's story that you mentioned, and more not only being things that happen in the game, but things that Edie commodifies and almost seems to actively encourage through the "family curse". 

I don't think it is wrong to think there's something quite vile about turning the actual murder of your 16 year old daughter into a graphic novel, turning your husband's death into a local fable through hyperbolic spectacle, neglecting to repair an incredibly precarious house (that the pregnant protagonist has to navigate over the course of the game) home to many children, or just generally enforcing reckless lifestyles and behaviours into the lives of your family for the sake of driving a trauma machine. The game definitely leaves a lot of room for inference in many cases, but for the most part it is pretty clear how certain characters die, and the reasoning behind their deaths is likely where the "vicious", "horrendously vile" points arise. I find Edie to be a considerably stronger embodiment of a word like "vile" than most any video game antagonist I've seen in a long time.