This guy is not an instructor, he may have completed his 50 hrs FIR and paid his money and has been signed off, but he is certainly not an instructor in the true sense of the word. How many have honestly not cut the grade for a grade 3? usually only under CASA FOI tests.On the other side of the coin you will find the crabby old instructor who may be better off not in the industry any longer either.
Anyone who yells or shouts at students should have a lesson/s in instructor/student relations and seek help. In all my years as a CFI i came across many many students who suffered at the hands of these incompetent imbeciles. If a students workload is so high as to warrant an instruction through a raised voice, that student may be nearing saturation point (doesn't hear) and perhaps the Instructor should "take control of the situation". You can load a guy up under a little pressure and he will still hear you and reply to questions and small talk, increase the pressure slowly and he takes a little longer to respond, until the guys workload is so high you could tell him you are bonking his missus and he still won't hear you......maxed out.......his brain can no longer handle the workload. If the guy is really goofing up, yelling at him won't help, so go back to INSTRUCTION etc etc etc.