If an opponent argues that a non-divisible concept can only be known by a non-divisible soul, the missing link must be supplied: why should indivisibility of the known object entail indivisibility of its knowing subject?
The commentary's replies concerning sensory instruments and mental representations challenge that entailment. Understanding a point or unity does not, simply by itself, rule out every possible bodily aspect of cognition.
Good reasoning separates the subject, its attribute, and the necessary connection alleged between that attribute and the desired conclusion. Here that connection is precisely what is contested.