The US lets immigrants leave if they want. Most US immigration issues revolve around people being forced to leave.

Or around people being prevented from working rather than forced to work.

I didn't have to get permission from my employer to look for another job. Not sure if you are trolling. Flagged the comment.

No it doesn't. Please educate yourself before contributing further.

H1-B is far from ideal to put it mildly, but it's about an order of magnitude away from what's described in the article.