She posted in public purposefully, and under her own name, whilst having a job where she's representing Disney with her name
That's a very different case from some private individual speaking privately in a situation where they don't represent their employer
For a more generic case, during your interview, you tell your prospective employer that you agree with their values and want to work together, then after getting hired, you tell them you disagree with their values. Should they still have to work with you?
Eg. You become a teacher at a Catholic school, but you only pretended to be a Catholic in the interview