As far as I’m concerned, « facile » has many meanings; depending on the context, it could mean “something easy to do”, “something that is done fast”, “something that is easily achieved”, “something that is enjoyable”, or “something/someone that is glib”.
The last one is not really a compliment, as you may guess. :)
What I’m trying to say is that it all depends on a particular context.
In your examples, one may think in a rather “negative” way and think that the prose is a superficial one, lacking of thoroughness and that the lecturer is glib lecturer.
As for me, I like to think positively, and I would say that the prose was easily achieved/written/produced and enjoyable to read/to listen to and that the lecturer is a fast and potentially enjoyable lecturer to listen to, as well.
Why be mean after all? :)
I hope that makes sense! :)