The point was made best because it presented a counterexample. Merely pointing out 'ad-hoc fallacy' (or similarly, my pet hate 'citation needed') might make the

The point was made best because it presented a counterexample. Merely pointing out 'ad-hoc fallacy' (or similarly, my pet hate 'citation needed') might make the author and a few other people feel good about themselves for seeing the flaws, but it's a lazy response which adds the smallest value greater than saying "I disagree", and is better suited to a points-scoring exercise rather than a discussion.