"How else are you supposed to learn?" It's a genuine question -- Sasuke isn't cut out to give Academy lectures about trajectory and poundage of pressure. He hadn't slept through those lessons, unlike others, but he hadn't gained much benefit from them either.

He's always benefited most from practical application, and that's what he uses now: rather than countering, he simply steps to the outside of her stab, throwing a hand out to give her a sharp shove on the shoulder.

It's not even an attack so much as an illustration of a point. "If you stab like that, you'll leave yourself open to a fast opponent."