If Sessions were serious about any of this two things would be happening right now. First the IT guy that swiped Hillary server would be charged with obstruction and 2 dozen other charges. Second the FBI would be investigating the murder of Seth Rich. Neither is happening so Sessions ain’t doing squat.
Rob Rosenstein has not given Sessions leave to charge even the low hanging fruit of obvious. (As your laser clear examples exactly represent.)
Rob uses Sessions for announcements only, or on occasion, he poorly briefs him for any required appearances, before investigative committees, on the hill.
Rubenstein makes sure Sessions knows so damn little that his testimony is a national embarrassment, making him look like a fool, a simpleton, and a seat warmer, who is in charge of nothing, actually.
Sessions is no simpleton, but his willingness to play that part is so striking and shocking that it gives way to suspicion that he is grossly under qualified, or carrying water for the swamp, by the gallons.
I think Trump covers for no one at the expense of his base. If he openly and regularly mocks Sessions, he is signaling that he is pizzed, and with good reason. Dayam.