Earlier quoted context omitted.
“Modern slavery” is definitely an exaggeration but many are also not quite so free to quit. The H1B is a “dual intent” visa, meaning you can apply for permanent residency while you have it. But you must maintain your H1B the entire time, which can be a decade or more for folks from places like India. You can transfer an H1B but it’s not easy and if you quit your job you must line another one up in 60 days or say good…
As long as they’re able to switch job and can leave the states (if they want to) I don’t think that the “slavery” word applies at all. And I’m saying this because there are places like Dubai where you very often get your passport taken on arrival, can’t leave the state and can’t really go work somewhere else. There is a lot more to say, but that qualifies as “modern slavery”.
Now: the system can own a slave.