The job with the HVAC company came to an end shortly after she posted the video. Her employer told her it had nothing to do with her performance, but was a head office decision due to a downturn in business, she said.

Sounds more like she was fired for revealing they pay an unlivable wage

Freedom of speech is from consequences from the government. That means you cannot be prosecuted for insulting politicians for example. But you can certainly be sued in civil court for the same thing.