Well, when some people use religion, they try to make themselves feel better or superior to others. Nazism is a bad example of that, where they used their religion to say that some people are not as good as others just because of who they are. They believed that people who were not of a certain religion or race were not as good and even wanted to harm them.
They believed in what they called "racial purity," which means they thought that some people were better just because of their race. This was a really bad thing, because it led to them hurting and killing a lot of people who they thought were not as good as them.
Basically, they thought that their religion and their race made them better than anyone else, and that this gave them the right to do really bad things to others. It's important to remember that this is a very wrong way of thinking, and we should always treat everyone with kindness and respect, no matter who they are.