I am on Blender v2.81.16 and collections in this version seem to work differently to the lecture in this version. When in Scene view clicking on a collection does not select the contents of a selection and even right clicking on the collection and choosing select objects appears to have no effect. If I switch to View Layer everything seems to work as expected, although as stated you do need to right click and select objects.
It is possible that I have set something up incorrectly, but I am guessing that the functionality has changed in 2.81. Possibly this might have been done to create a clearer distinction between the Scene and Layer views. Any observations or thoughts on this?