They are "free" to change jobs in the way that one is "free" to disparage a judge during their trial. The fact that there are many, many hurdles to doing this,

They are "free" to change jobs in the way that one is "free" to disparage a judge during their trial. The fact that there are many, many hurdles to doing this, not the least is finding a company that is willing to pick up sponsorship of that visa, makes that "free", not really free.