Thank you for the additional information.
Having been on both sides of the fence your initial post tickled my instructor nerves a bit.
One thing that continuously needs to be emphasized and that A LOT OF PILOTS at all levels in the industry do not understand is that there is a major difference between Procedures and Techniques.
Some schools/instructors teach to turn the transponder to ALT (mode C) immediately after start up on the ramp as part of their pre taxi checks.
Some teach prior to entering the active runway as part of pre take off checks.
Some do not turn individual avionics off just teach the use of the avionics master switch and the transponder is always left in AltZ
When operating from a non towered airport none of this matters, it’s all adequate.
Situation changes when you fly from a towered airport where it may he required to taxi with the transponder either ON ( no alt info) or on ALT ( mode C)
This should be on the airport notes.
Long story short:
You may have learned one of the above 5 variations in technique/required procedure and you operating at this particular airport required another.
However it sounds more like a technique issue on the part of the instructor.
Certain techniques are more appropriate then others in certain situations.
Question is whether you did something you shouldn’t have done or vice versa or if it was in the way you did it.
You’ll learn that flying with some is the equivalent of nails on a chalkboard but none of it is intrinsically unsafe or incorrect.
Annoying as f**k though.
But that’s personal.