Non-professional gear advice

Hello dear people, today I‘ve brought Nikon Z6iii with 70-200 f2.8 to kids fencing competition to film my kids compete. Ended up being told off by an organiser and asked to hide camera because “use of professional equipment is not allowed”. Good sir has struggled elaborating what counts towards professional and rudely suggested myself and my kids will get removed from the event.

Regardless of the organisers loutish formulations British Fencing rules do indeed make it hard to use any equipment that may be perceived as “professional” by jesters of all sorts.

I am looking for equipment suggestions of what could produce decent images of fast moving subjects in poorly lit sports halls.

EDIT, in avoidance of doubt:

I did not fight the organiser, I simply asked “what makes this equipment professional?”. In case you struggle seeing reason in my question, I could have:

* put on different lens

* mounted 70-200 on lower end body

* brought lower end body+lens combo (still interchangeable lens)

* shot with point-and-shot/phone

I assure you my formulation was very reasonable and precise.