I'm not defending Trump personally - but as a concept, lets dig into this a bit.
So someone gets into a position of gaining a vast amount of knowledge over a short period of time from experts and consultants...
Do you expect that their perspective hasn't shifted, or that they will stick to their guns no matter what?
Because that's politics as usual - ignoring new evidence an voting/acting in a manner to support your original stance... never changing (especially drastically)
But isn't the way it should be just this - that new information should inform your decision and, if you're open minded, you should consider changing your stance if the new information supports it?
I'd take someone who changes their mind with new information over someone who sticks their fingers in their ear when information that opposes their viewpoint comes to their attention. Even if their decisions are in disagreement with me, their ability to change their stance says that they are at least making those decisions as opposed to having those decisions decided by what party label they strap on their chest...