For children gnomes are real people, even if they don't look human. They live in what can be described best as an adult world for minors. Gnomes chased by a bad tempered owl or tripping over their own feet and falling into a shallow brook is sheer DRAMA.
If gnomes behave naughty and provocative, it's always in a childish way. From the point of view of grown ups. They don't take kiddie stuff serious. They make fun of fairies and pixies and gnomes, but in a typical adult way: by sexualizing them. The preceding episode already showed some naughty ones; the Mooners. Grown ups tend to take it lot further.