Okay kiddo, let me explain it to you. You know how some people can be really mean and hurt others just because of how they look or where they come from? Well, a group of people called Nazis did some really bad things a long time ago, like hurting and killing millions of people just because they were different than them.
Now, we don't like that kind of behavior and we don't want to encourage anyone to act like that again. So some countries have made rules that ban people from showing symbols that are associated with Nazis, like the swastika or the SS symbol.
It's kind of like when you play a game with your friends and someone tries to cheat or do something mean, you make a rule that says they can't do that anymore. These symbols remind people of a time when lots of bad things happened, so we don't want to see them around.
It's important to remember that everyone should be treated with kindness and respect, no matter where they come from or what they look like. So, it's good that we have rules in place to prevent people from promoting hateful ideas.