There's another L-R split that's worth looking at.
In games where they faced a lefty starter, the Yanks had an .832 OPS.
In games where they faced a righty starter, the Yanks had a .761 OPS.
What this shows is that they did do much better against lefty starters than righty starters. The difference gets shaved when you include relievers, probably because so many relievers are righties.