I agree. I haven't seen anything about re-usability on the SLS which is just nuts. I actually think Airbus' approach with the Adeline is a more realistic approach, but they don't seem to be nearly as far along as SpaceX is. Any sort of re-usability is clearly better than none.
My main disagreement with Ms Garver is that she portrays this as a turf war. Musk has an edge of bravado about him that can make him seem a bit un-serious. Re-using rockets sounds great. Re-using them on the same day sounds like a greedy businessman trying to skimp on safety checks. I think this is what NASA finds upsetting. I may be very wrong.