My interpretation is that the ketchup head sees the superficial similarity of a splatter of red liquid and says he can do that, but he doesn’t actually have the inherent qualities that give the bullet’s splatter its emotional and artistic meaning.
No matter what, a splatter of ketchup can never carry the same meaning as a splatter of blood and other bodily fluids, so the ketchup head’s ability to make something visually similar does not translate into him being able to make something artistically similar.
My interpretation is that the ketchup head sees the superficial similarity of a splatter of red liquid and says he can do that, but he doesn’t actually have the inherent qualities that give the bullet’s splatter its emotional and artistic meaning.
No matter what, a splatter of ketchup can never carry the same meaning as a splatter of blood and other bodily fluids, so the ketchup head’s ability to make something visually similar does not translate into him being able to make something artistically similar.