My thought was that decapitated Marie Antoinette was meant as a celebration of the French Revolution. The same Revolution that replaced the old system, the oppressive and violent monarchy, with the even more oppressive and violent Jacobins.
Tough to precisely interpret symbols at any rate and maybe it was done simply for shock value, and no underlying subtext was intended. But I doubt that.
Peripheral to this, Victor Hanson, amongst others, has made frequent comparisons between the modern left and the Jacobins. The Impending Thermidor Reaction in Jacobin America A snippet from the article: "Almost everyone who originally had opposed the absolute monarchy, and, like the Americans, wished for a constitutional replacement, was eventually executed by revolutionaries who were then executed by more radical revolutionaries. The longer and more radical the revolution ran, the meaner, dumber, and more deadly the revolutionaries who emerged from the woodwork." Later on, after making the comparison between the Jacobins and the current state of America and the American left: "As our woke version of the Jacobin revolution accelerated, society itself began to unwind—as expected given America relied on meritocracy, free expression dissent, the rule of law, forbearance, and tolerance."
Hanson does suggest a glimmer of hope exists, in that eventually reality has to triumph over the absurd. But I doubt that too.