The photos are graphic for the link. People are cutting themselves in solidarity with Amber Heard.
In the Old Testament, self-mutilation was a common practice among false religions. First Kings 18:24–29 describes a ritual in which those who worshiped the false god Baal slashed themselves with swords and spears, as was their custom. Because of the traditions of pagans, God made a law against this sort of practice. Leviticus 19:28 says, "Do not cut your bodies for the dead or put tattoo marks on yourselves. I am the LORD." In the New Testament, cutting oneself was associated with someone who was possessed by demons (Mark 5:2–5). It was characteristic of behavior caused by evil spirits.
This is horrible and people are mentally ill, possessed or both.
I don't believe in Darwin's version of 'natural evolution' or 'natural selection', per se, but if I did, this would be a classic case of it.