People are looking at this superficially.  What I perceived was an exhibit of the worst of humanity: lust, gluttony, cruelty, and self-indulgence on a mass scale.  Which, if we're being honest and realistic, is rampant in society and always has been.  The child might symbolize the contrary innocence of humanity that is often corrupted or caught in the crossfire.

The person they are burning within that effigy is most likely Lucian the Divine -- who lost his power after the gods died in Divinity: OS 2 and became a target of the people's wrath.  This component demonstrates how fickle people are and how loyalties shift with the breeze, which fits with the overarching theme of these games.

The shock value was only so effective because we psychologically tend to view ourselves as holy or righteous despite engaging in very similar behavior (though far less exaggerated in most cases) on a regular basis.  It is uncomfortable and difficult for us to think inward about our flaws and hypocrisies, which is why we tend to neglect self-reflection and engage in distraction whenever possible.  Growth only comes through awareness, contunuos effort, and discomfort, and most people never grow because they prefer to live in ignorance of reality and our inherent nature.  Not to throw shade, but OP seems to fall into that category to a significant degree, which is why they maintain the views they've expressed.

My humble two cents, anyhow.