Earlier quoted context omitted.
It's obvious, and they should have known. In my experience the best people to educate the newbies are the people who were newbies a year ago. They know what the roadblocks were for them, and the don't know 'too much' as to complicate things.
It's funny because education is actually is backwards here. You're supposed to want to be taught by an expert in the field.
If the expert has enough "intellectual empathy" to put themselves in noob shoes then they can still teach well. However, if they can't state without reservation that 1+1=2 then they are no good for beginners.
I used to say "the following statement is a lie, but it's true enough for today." If a (usually advanced) student asked me what that means I'd go into the details, but you need to lay out a solid skeleton before you can start hanging irrelevancies on it.