"Well, kiddo, there was a time when people who were attracted to the same gender as themselves were not treated very nicely. They were not allowed to get married or even have certain jobs. They wanted to be treated the same as everyone else, and that's where 'gay lib' comes in. Gay lib was a movement where people fought for the rights of those who were attracted to the same gender.
Now, the University of Missouri is a big school where people go to learn and get degrees. Some people who go to this school are attracted to the same gender. But, some other people at the school did not like that and did not treat the students who were attracted to the same gender very nicely. So, the students who were part of gay lib decided to do something about it. They protested and talked to the school leaders to try and make things better for everyone at the school, no matter who they were attracted to.
It was a big deal because everyone deserves to be treated nicely and fairly, no matter who they are. Gay lib stood up for their rights, and the University of Missouri had to listen and work to make things better for everyone."