Okay, so imagine you and your friends love to play soccer together every day after school. But one day, a new kid moves into the neighborhood who loves basketball and doesn't want to play soccer with you all. Now, it's okay if he likes basketball more, but it's not okay if he makes fun of you and your friends for playing soccer or tries to make you stop playing altogether.
Something similar can happen because of religion too. In the United States, people have the freedom to believe in any religion they want or not believe in any religion at all. However, sometimes people make fun of others who believe in different religions or try to stop them from practicing their religion. This is called religious discrimination.
For example, if you go to a school where most people are Christian, and you are Muslim, some kids might make fun of you for being different. They might call you names or exclude you from playing with them. That's not okay because everyone should be treated with respect and kindness regardless of their beliefs.
Religious discrimination can happen in other places too, like at work or when someone's trying to rent a house. It's against the law to discriminate against someone because of their religion, but unfortunately, it still happens sometimes. People should always be aware that everyone is different and that diversity is a good thing.