From a pure theoretical view, I can see how/why, if it were to turn out to be true, the Gummit would be hesitant to acknowledge NHI.
What she says about pictures and spacecraft isn’t to me the big thing. Listen to what she said about “deeper theories and concepts of historical things and Religion”
I see it as 3 psychological Steps
1) It’s one thing for them to admit, “hey there really are aliens in spaceships, we’ve recovered some here’s the physical proof and we’re reverse engineering their technology ”.
Most I think would say, “yeah I knew it”, and/or “how’d they get here? What about the technology?, when do we go to Alpha Centauri? Can they fix my ‘56 Chevy fuel pump?”
But by and large at this point I think the majority would accept it. We’ve lived through crazy times the past 20-30 years.
2) Even the next step of “… and they’ve been here for thousands of years and keep coming back to visit” ..It would help explain some ancient stuff like pyramids and cave drawings of flying machines.
A much bigger concept to get one’s head around, but ok it doesn’t fundamentally change who I am.
3) But it’s a whole ‘nother thing to take the ultimate leap and say “welp they’ve been here all along, they are us. We’ve been one big Petri dish experiment, the Bible (or cosmic evolution if that’s your preferred explanation) is indeed a roadmap but not like you think and meant as a way to distract you from the reality that everything you believe, everything you think you know, everything you’ve been taught is a lie.