Joseph, you’re the one who is claiming that it is absolutely assur so you are the one who needs proof. Your post was not any kind of proof. Proof would mean something like a teshuva from Rav Moshe Feinstein zatsal saying that it is absolutely assur for any Jew to ever be a judge.
And I don’t even think that’s proof because there could be different opinions. The fact is that there is no way for you to prove it, because you don’t know enough to be able to make such a blanket statement. This is something that only a poseik can answer, and you have no business poskening that this lady is doing something assur.