Why would it need to be presented to POTUS at all? Most OIG reports are released without bothering POTUS with a preview. Same with preview to Congress.
Setting that aside, this part of Horowitz work is taken by those who are walling Sessions off, as being about the Hillary campaign, not about FBI/DOJ conduct. With Sessions being cut-out, Rosenstein becomes the DOJ->WH conduit.
Disturbingly logical.