I don't understand too

I sat in the MRT this morning after a tiring soccer session. Upon seeing 2 old person (You can see obviously they are old, they are not those you have to think twice if you should offer the seat so as not to offend them.) and a little kid standing infront of me, I stood up. I mean, it is common sense that I am giving up the seat to anyone of them. But no....this lady (prob late 30s) just rushed to the seat. I glared at her, but she gave an act showing her husband her knee hurts. Fine, I let that pass.

One stop later, a seat was emptied. Her husband rushed to seat down. I just shook my head. So happen another seat beside the wreteched woman was free, she actually put her hand on the empty seat to reserve it. She waved in the direction of the old lady. I thought she was doing something good, but NO.....she is waving to her son (prob in Pri 6) to take the seat. Her son just happily took the seat while the old lady stood infront.

I gave them the benefit of the doubt, maybe the old lady did not want a seat. But their actions do not justify them even trying to give up the seat to the old lady.

Few stops later, a seat beside them was free and finally they old lady sat down.

I don't understand humans....is it so bloody difficult to give up the seat to someone who needs it more?