[CharlesW]

> Actors, comedians, and politicians all have memorized scripts, lines, routines, and soundbites.

They recite some of the time, but most their overall speech is improvised. Generally, people in these kinds of roles are pretty good at that too.

> In this case, the comment is both contradictory and harmful. Literally no one learning or teaching communication says that "uh" and "um" are good habits.

It depends on how meta you want to get. As a beginner learning how to give speeches, you work to expunge these kinds of "filler" words. However, at "expert level" you might use these words to seem more "authentic", and/or to appear as if you're forming thoughts for the first time.

It depends on the audience and what you're trying to communicate, which goes beyond what you say to how you say it.