For example: as I have darker skin, I had been called very racist things by my classmates, when I was very young. As I am a Shia, a lot of people in Punjab also had a lot of misconceptions about my sect, & even though they were very open (almost in an abrasive way) about their misconceptions, they did not express it in a harmful way, or maybe I never felt threatened by it.
There are problems in every society, & even more so in Pakistan, but I also think people need to "develop thicker skin".
P.S. And to be honest, I find it quite hard that people wouldn't eat with her because she was Christian, especially when she's from cosmopolitan Karachi & going to an elite school. I live in interior Sindh, we have a lot of Hindus working here at very good positions, we eat together, we laugh. We embrace, we go to each other's religious & social events. We're all very good friends, & we talk to each other openly, including the plights of different groups in Pakistan. But at the end, despite all of Pakistan's problems, we'd rather be part of the solution, & stick it out, rather than giving up on Pakistan because of the "bullies in the playground".