Okay kiddo, so there's a group called the American Family Association and they didn't like some ads that were put up on buses in San Francisco. These ads were promoting a TV show and had some words on them that the American Family Association thought were mean to their religion. So they sued the city and county of San Francisco because they thought the city should have taken down the ads.
The city and county of San Francisco said that they didn't have to take down the ads because they were protected by something called the First Amendment. This means that people are allowed to say what they want, even if other people don't like it.
The American Family Association didn't agree and said that the ads were still mean to their religion. But the court decided that the First Amendment was more important than the American Family Association's feelings. So the ads stayed up and everyone had to learn to get along even when they don't agree about things.