ATC have cleared you to land. Then they see something to change that, and cancel the clearance and ask you to go around. No problem so far, and everyone is reasonably content. Then the pilot asks if he can do an orbit instead of a full go-around. ATC agree to this.
The pilot then cocks up a simple activity by not putting enough power on, leaving the flaps down, going slower and slower and, maybe, stalling and crashing into the ground.
We all know this has happened and that is why many instructors have a mantra - never orbit on finals.
But really, it is just basic flying, and a well trained pilot will do what is necessary to ensure that he maintains appropriate airspeed - putting on PLENTY of power - and I don't think we should train pilots to the lowest common denominator. Instructors should (IMHO) train students to deal with this matter, and not just say "you must not do it". That is not training.