Part of the problem is that by European standards, unions in the US have been treated as pariahs for a century or more, and been fought relentlessly, whereas in Europe, parties supported by unions have been in power for lengthy periods in lots of countries.

US unions won tremendous concessions early on, at horrible costs to their members (a lot of blood was shed) - they were instrumental in laying the ground work for the 8 hour working day (and most of the world celebrate May Day in their honour, and in commemoration of the Haymarket Massacre), but unlike Europe where the workers movement continue to grow in influence and eventually effectively won a place at the table supported by governments friendly to their causes that forced business to learn to work with unions in a completely different way, the antagonism just kept escalating in the US.

If you treat people like shit long enough, they'll do their best to live up to the image you portray of them.