I would have thought the opposite (Rizzo wants him benched, Davey wants him to play).
I have been trying to catch some of the discussion on XM 89 MLB the past two mornings, and perhaps someone here can report on that, because I haven't been able to catch as much of it as I would like. But I get the impression that they think that the argument between Davey and Rizzo was all about Harper and his tantrums. And the argument is over benching him. (They would, indeed, be taking about sending him down, except that the minor league season is almost done.) I don't know for sure who is taking which position, but presumably, Davey wants to bench him and Rizzo wants him to play.