Nedbank refused me my right to withdraw my money

Are there any special rules with regards to ATMs? I went to the Oxford branch, East London to withdrew cash. Because of safety reasons, I opted to withdraw using the inside ATM. While I was queuing, the lady from the front desk came to me to specifically remove me from the que, saying that I was young enough to que outside. I understand the preference given to pensioners and senior citizens. But even after I explained my reasoning she removed me. I told her that, should the be more pensioners coming after me I will allow them to get in front of me. But she just completely refused. Is it because Nedbank is giving us a favor by giving us our monies when we need them? If there are specific rules on ATMS. At least let them be known clearly. Put up signs so that we can be aware.