I am annoyed by airport staff's abrupt questions

Recently, my family and I were preparing for an international flight. As we pushed our suitcases toward gate D1 at Tan Son Nhat Airport, a security guard quickly approached and asked, very abruptly, "How many people are going?"

After I replied that there were two of us, the staff member demanded, "Show me your passport and plane ticket."

At that moment, my relative's phone had run out of battery, so he could not display the ticket. Even though the passport contained a valid visa, the staff member looked visibly annoyed, turned to the door, and said, "Then go out, charge your phone, and come back."

Another staff member added, shouting, "You there, please go out."

I found this behavior extremely impolite but chose not to argue loudly. Instead, I went to another gate to approach the check-in counter.

This was not the first time I've encountered such attitudes. On a previous occasion, I clearly explained from the start that I wanted to accompany my elderly parents to the check-in counter in case they needed assistance. The staff at the departure gate spoke in a superior tone, asking me to repeat myself and telling me to "explain clearly," as if my request were unreasonable.

Where do airport security staff get the right to treat passengers so rudely? When will airport employees learn to interact politely with the people they are supposed to serve?