Going while the going's good
Loverro is head of NASA's manned spaceflight division. A part of the organisation that has been developing their latest Space Launch System since 2011. A project that will build and fly 3 manned missions for sure and more planned but not confirmed, after that. The rockets are cobbled together from old Shuttle left-overs and will still cost around $2 billion per shot.
Compare that with Space-X. The company has gone from zero to manned operations in 10 years and expects its crewed Dragon flights to come in at $160 million a pop - due to the inherent reusability of their system. With a design capacity of 7 crew per launch (though I doubt it will ever cram that many in - at such a low cost, why bother?)
If I was head of NASA's manned operations, I'd want out before other people in the organisation start making these sorts of comaprisons, too.
Afterthought Perhaps a higher-up has already had that conversation with Loverro. Something along the lines of "Hey Doug, you do realise that if this Space-X flight succeeds, we're going to can your manned missions and just buy seats with them instead?"