In addition to slavery, Americans also had The Frontier. A man who didn't like the wages offered had the option to go make a homestead.
European culture is likely to have been far more shaped by feudalism than American culture is. You don't have to individually remember something for it to have an important effect on your values and actions.
BTW that line of thinking is ridiculous. Europeans and Americans learned about feudalism the same way, from history books. No one who was around when labour laws were going into effect has first, second or third hand knowledge of feudalism, slavery or working conditions during the Industrial Revolution.