Eh, maybe, maybe not. Language is powerful. Replaced the "pissed off" descriptor in that sentence with "shafted" or "fucked over" and it dramatically shifts the narrative.

Even describing the employees' emotional state is unfair to labor, as emotions may not have entered into the decision to protest and emotions are perceived to be less important than cold business logic. Thee workers may need the benefits to survive in their community. When an employer cuts wages or hours or jobs, they say that there are no emotions involved, it's just business.

If I were you I would be more careful with the connotations of the language you choose, being mindful of how it is likely to be perceived.

> notably corrupt

What about their employers?

I think unions are painted with a very broad stereotype by people who don't know them (including most people on HN, I would guess) and held to different standards than businesses, many of whom are notably corrupt.