In ways that no one should be proud of, and anyone with a conscience should at least recognize needs redressing-even if the outcomes are things they as an individual wouldn't directly benefit from.
"At-will employment" laws mean that the burden of proof for the cause of firing is on the employee, rather than the employer. This gives free rein to employer's to fire workers considering unionizing, so long as there is the barest pretext of another cause. As forming a union becomes economically risky, unions decline, or fail to form in new industries.
Unions have been attacked in the US, through explicit policies meant to defund unions, and to prevent unions from forming.
A short googling for for "history of workplace safety in the us" reveals that unions had a hand in at least that. Probably in several other things you take for granted.
In my opinion it's a mistake to think that things like that cannot deteriorate away after they've been achieved once.
Just the stories about how union work is handled on US movie sets is just baffling. Directors can't even touch the lights without an Official Light Mover Union member doing it. If they do, all union people will just walk off set and that's the end of it.
In most European countries unions are more about collectively agreeing to some basic rules like wage, hours worked and other compensations.
Someday maybe our betters in Europe will understand that the American experience with unions is different than that of Europeans. And that American unions are a very different animal. Until that time, though, keep thinking we're just idiots.