Why do elderly get pissed at the young for not offering them a seat?

When I was on the bus yesterday this elderly lady was scolding, "I'm waiting for one of these youngsters to get up and let us sit down!" None of them did. Some of the elderlies got angry. One teen said, "Why are they getting pissy. We got here first."
So I got up and offered the lady to sit. A guy did too. She was like, "Well thank you young lady. At least SOMEONE was considerate to loan us a seat."
The other elderly lady got off the bus angry scolding, "I'm just going to get off because these youngsters refuse to lend us a seat and selfish little bastards!"
The bus driver didn't do anything about it. If it was a younger person that complained about wanting a seat, they probably get scolded at.