I mean, even stripping away the whole Black Moon Clan element, it’s so tragic. She’s a small child who’s been forced away from her loving parents. Children need their parents. All Chibiusa has of them is her memories. It’s especially painful whenever she sees other children with their parents, which is often. She’s a remarkably strong and brave girl for not giving in to her desperation of wanting to see them again.
Then you add another layer: Chibiusa is indirectly responsible for everything that has happened. By holding the Ginzuishou, it disappeared inside her when it was needed the most. The Black Moon Clan attacking Crystal Tokyo right after she held the Crystal was just a freak coincidence, but the entire time she’s in the past, Chibiusa wholeheartedly believes that she somehow summoned the Clan when she held the Crystal. Not to mention that, because the Ginzuishou was absent, her parents were gravely injured.
Can you even imagine living with that horrible guilt?
So she’s a brat. Literally half of the kids I know are about ten times worse than she ever was. What’s their excuse?
That’s why I’m just put off by the Chibiusa hate in the fandom. I know the dub did her no favors but it’s important to watch how she grows. Watching her grow from a frightened, lonely child into a well-adjusted, well-loved girl well on her way to becoming a true lady is one of the best character developments in the series.