You kind of just proved his point rather than negating it. Even if it were true that 30fps means the game is more "sluggish" what if the designers want the gam to feel "more sluggish" or at least have designed the game to feel slower in reaction in that manner for tension.
You can make the game / controls feel sluggish without bringing down the framerate.
Edit: And as SeanSpeed said 30fps with for example mouse controls makes you feel totally disconnected to the game because it's unresponsive, like i'm playing a game with with 500ms or something.