I think there is a grain of truth to be recognised that in different cultures it isn't seen as abusive, and that we view men who behave in that way as abusers when they would not view themselves that way. So, say a 60yr old tribal elder taking a 14 yr old 3rd wife wouldn't be seen as an abuser in their own community. They would not be doing anything transgressive in that community.
However it's unacceptable and the culture there needs to be challenged until it becomes transgressive. Does that make sense? It's absolutely not a reason to say 'oh perhaps we're wrong after all, and sexual relationships with children aren't always a bad thing.' They absolutely are. Obviously.