He has a really valid point. Yes, Ortiz has been good, but this is his line against LHP this year:
.192 BA, .264 OBP, .273 SLG, .536 OPS, 1 HR
Those are clear platoon numbers. There isn't even an argument. Now, Lowell is no guarantee either, but over the course of his career he has been a better hitter against LHP.
It's a good idea, don't knock it.