As a little boy, you know that three things are undeniably true. First, you are going to be an astronaut when you grow up. Second, dinosaurs are the coolest things on the planet. Most importantly, all girls have cooties.
With this knowledge, it's hard to come into contact with a girl as a kid. You don't want to get cooties because that is a fate worse than death, regardless of whatever cooties entails. You'd be ridiculed and cast out from society for having them. Yet once you finally make contact with the dreaded "girl" for the first time, it's an occasion of great magnitude. That's why watching this little boy hug a girl is such a wonderful thing to experience.
Wasn't that priceless? See, hugging a girl doesn't really give you cooties! But don't tell anyone at school that you did that, because they are going to persecute you if they ever find out you hugged a girl!