I never once got the impression that Julia was dumbing her presentation down to a juvenile level to make it more accessible.

Rather, the impression I get is that Julia is as enthusiastic about this stuff as anyone has ever been about anything, and that she has no pretense of having known any of it last week, nor does she care if you did.

It's pretty charming and unique combination (it's rare enough that when status-conscious adults come across it, it reads juvenile!) and is my favorite thing about the way she writes and presents. When she writes about stuff, she doesn't have to judge each element she's discussing for whether it's interesting or worth calling out; it's all interesting. That's a good way to avoid missing interesting observations, I think.