That's a good point. But it's not an either-or situation. The teacher needs to protect herself, and outside organizations need to get involved, strongly involved.
I might catch some flak for what I'm going to say now, but here goes. The old-time teacher unions never would have stood for this. The old-time union leaders might have been corrupt, but they were tough. Many were WW II or Korean War vets. If any member was treated like that lady, there would have been a formal protest from the union, and then the threat of a strike. And I'm not just guessing here. I've seen that first-hand.
But those old-time union leaders are gone. They have been replaced by ultra-liberal, politically-correct stooges. I seriously wouldn't be surprised if that lady's union filed a paper supporting the principal.
Good point; the wealthier the educators got (many can now take skiing vacations during "winter breaks"), the more cowardly. And when they do stand up, they stand alone.