1. This was not done by some descending horde defacing a piece of beautifully carved stone whose meaning was long forgotten in an act of vandalism.
This was done by once pagan converts to Christianity for whom this was once an object of veneration, with real spiritual meaning.

2. They were actively cutting ties with demons they once worshipped. This was real. It remains real. Only in a society that has lost most of its religious feeling, enclosed in a techno-materialist prison could we look back and think, “How could they deface such beautiful art?”

3. In these pagan cultures this was real. They understood that these statues were the focus of the worship of false gods, demons, principalities and powers. This is also why food sacrificed to idols was such a big deal in the early church.

4. So someone, very likely a pagan convert who used to worship using this statue as a focus, made a conscious break with their past, breaking the power that the demonic entity had in their life, cutting off the face, carving the cross as an act of both desecration and devotion.

5. And while we are the subject of looking back on the past, applying modern materialist categories backwards, Christian sexual prohibitions were not seen as restrictive, but in a world where sex was everywhere and tied to demon worship, Christian sexual morality was liberating.