Work visas are used as a method of coercion by US companies, and Facebook knows how effective employees can be when they are coerced. I knew of a professor wit

Work visas are used as a method of coercion by US companies, and Facebook knows how effective employees can be when they are coerced. I knew of a professor with a work visa who spoke out against a University policy of oversizing certain classes. They revoked or did not renew his visa (or however the termination of an employer-sponsored visa works), and mid-semester he had a nervous breakdown, was forced to short sell his house, and was forced to go back to his home country.