Combine H1B with debt like for cars, education, housing, etc., and that’s full-on indentured servitude. People under such duress maybe convinced to work for $30/hr or less.
Education debt may be different, there's a good chance that was incurred in the country of origin, so it's likely the lender has recourse.
One of my friends left US to get married, but his visa was denied. He had to sell all the stuff, cars remotely (with friends help) and it took whole 6 years to come back (because of the visa quotas, denials etc). But he eventually was successful in returning and it's good he settled all his debt when he was kicked out with a visa denial.