The people, as in the ignorant masses, usually can't handle knowledge of everything that goes on or is necessary in running the kingdom. They're not informed enough to make the decisions or to understand the situation.
You just don't blurt out shit like that and only leave them with the "shit's fucked and we're lying to you" image and not explain why it's been necessary to keep it on the down low or what measures are being taken or so forth.
She just unnecessarily instilled fear and distrust into the hearts of the people at a trying time. Nothing, absolutely nothing good comes out of it, but instead a lot of bad stuff does. It could lead to civil unrest, it could lead to a civil war where a lot of people would die.
It's a meme that being honest is always for the best no matter what you say to whom or how. Some things need to be kept hidden so that things will run more smoothly.
There's no explaining it away. Star fucked up. She ruined her own image and the people's trust in her family dynasty, the relations of the MHC to her parents and also her parents' trust in her, ONLY because she was a petty fucking bitch who didn't want to respect a much-loved ancient tradition that's important to her future subjects because she personally found it boring, and so she wanted to humiliate her parents. And also, you know, boast a bit, that part about how she's the best and a thunderstorm etc
She doesn't think of the consequences of her actions, but acts out of selfish emotion. It's who she is.