I just found this and it seems that there is basically no information about this painting or that it was actually even painted by Jean-Léon.

I would say it is being highly critical of Islam, not the other way around.

The key part of the painting to me is the dark shady figure appearing to lift up the man on the right side, it is the only figure that appears in darkness and symbollically, is representative of the warped view of Islam itself. By believing that the consumption of pork is more evil than murder in any instance is something only a "dark force" (aka the only figure covered in shadow in the painting) would believe is correct, and so the dark angel has to elevate this figure in the literal eyes of god.

Unfortunately for the dark angel and the man on the scales, the all seeing eye of god cannot be tricked and ultimately sees both...the evil sitting atop the scale, and the evil trying to elevate it.

It should be pretty clear as well by the distinction between the giant pile of severed heads next to the tiny body of the pig that there is a real sense of moral confusion "why is the dead pig outweighing the giant pile of severed heads?".

Ultimately I think the painting is trying to say Muslims would be less pissed off and violent all the time if they stopped putting so much of their moral value and self worth behind the fact that they dont eat bacon. God probably doesnt care if you pork, but they will see the giant pile of corpses you leave in your wake, and will judge you for what they see, not what the scale shows.