I don't think pitchers are coded to have intrinsic advantage over certain handedness by platoon attributes as in Contact and Power for hitters. The in-game commentators are simply making general baseball comments I think.
Much of platoon effect derives from the delivery of a pitcher and how his pitches break relative to the hitter, so if the hitter AI in The Show is actually coded to respond to these elements realistically, I would expect some in-game pitchers to have more pronounced platoon advantage over others. But I would not be surprised if the hitting AI isn't that detailed though; otherwise we don't have to have split attributes like Contact & Power for hitters the way they are.