I’d argue the main difference is that it involves a crime.
I’m not completely sure that torture itself constitutes a crime (though I’d be surprised if it wasn’t), but manslaughter/murder is. With few exceptions for medically assisted death, killing someone is a major crime. Presumably, we don’t want to promote people profiting from extreme suffering and death.
I also think there is a time and place for censorship (ex CSAM).
“Objectionable” is a subjective term, but “illegal“ is not.