What is strange though is that we hear all the time about unions being sometimes full of corruption, but not about the other political players.

Aren't the democratic and the republican party sometimes corrupted? What about the Koch Brothers and the Tobacco companies and the Bitcoin/Blockchain sector and the fossil fuel companies and the alcool companies? What about the tech monopolies? What about everyone that has a political stake in everything?

Who decided it was important to associate corruption with the unions and only the unions?