So I explained.
You know how most kids in your class have a mom and a dad, and you know how the moms and dads are married, like me and your mom? Well, most married people are men married to women, but sometimes men love men and want to marry them, and sometimes women love women and want to marry them, and when we put that sticker on our cars, it means we think they should all be allowed to do that. But some people think that men should only marry women, and women should only marry men. I know, it is silly.