You don't know that. Some violent animations got marked for kids because they contained "bright colors".
For example, Doki Doki Literature Club, a PSYCHOLOGICAL HORROR GAME, got marked for kids.
But boy oh boy, it isn't. (One character hangs herself, another stabs herself, and one attacked the player.)
Heck, the game even SAYS that it's not for kids, and it's only for those 13 and over.