That's a commonality in a lot of media that's ostensibly written for younger people, whatever the country. When you have a story where younger protagonists are going to be going on dangerous adventures or getting up to risky heroics, parents present a bit of a narrative problem. In a real-world situation, you'd expect parents and other adults to want to protect their kids, hold them back or forbid them from dangerous things, or even fight for them so they don't have to, keeping the kids from being the heroes themselves.
I think writers frequently fall back on two solutions to remove parents from the picture, and give young protagonists maximum room to have adventures:
1) The parents are mostly out of the picture; they're well-meaning and supportive when they appear, but tend to be shown as goofy, incompetent, and out of touch. They are often blissfully unaware of their children's secret lives or heroics, and may even be physically separated from their kids by distance or circumstances. Their children may also have heroic alter egos, or may be whisked away by the story's framing device to an alternate world or on a special quest that separates them from their parents while they're questing. Basically, it's a modern stand-in for the old fairytale device of "And thus So-And-So said farewell to their parents, and set out to make their way in the world". This is common in more upbeat or cheerful stories, or those aimed toward younger children, though it happens in more serious stories as well. Anime: Sailor Moon, Pokemon, Escaflowne, Inuyasha. Cartoons: Fairly Oddparents, Scooby Doo, Inspector Gadget. Stories: Ender's Game, Paranatural, Harry Potter.
2) Their parents are absent from their children's lives because they're always working, are deadbeats, abandoned the family, mysteriously disappeared, need rescuing, died, or are even antagonists or villains in the story. Sometimes their absence is some part of the protagonist's call to adventure; they set off to discover their parents, rescue them, or defeat them. The children may also run away from home, or be separated from them in the wake of tragedy or disaster. Common to more gritty or serious stories, or those aimed at older kids or teens, though comedy and upbeat themes work fine with it too. Anime: Record of Lodoss War, NGE, YuYu Hakusho, Dragon Ball, Fullmetal Alchemist, Naruto. Cartoons: Adventure Time, Thundercats. Stories: Harry Potter again, Eragon, Lord of the Rings (Sorta? Hobbits are kinda symbolic of children).