God is accountable to the laws of logic; if he claims to be morally absolute, then the must not be morally relative (which he is, based on the example I have demonstrated).
I wonder how Aquinasfan would deal with this, given that Aquinas agreed that it was impossible for God to create (for example) a triangle with internal angles that did not add to the sum of two right angles (assuming that we are drawing our triangles on a Euclidean plane).