NEW YORK — I was on my way home on the Cairo Metro, lost in thought as I listened to music when I noticed a young Egyptian taunting a Sudanese girl. She reached out and tried to grab the girl's nose and laughed when the girl tried to brush her hand away.

The Sudanese girl looked to be Dinka, from southern Sudan and not the northern Sudanese who "look like us." She was obviously in distress.

I removed my headphones and asked the Egyptian woman "Why are you treating her like that?"

She exploded into a tornado of yelling, demanding to know why it was my business. I told her it was my business because as an Egyptian and as a Muslim who was riding the Metro, her behavior was wrong and I would not stay silent about it. I knew she was Muslim because she wore a scarf.

I told her that the way she was treating the Sudanese girl made the scarf on her head meaningless. Her mother asked me why I didn't cover my hair and I replied that I didn't want to be a hypocrite like her and her daughter.