It was probably Hollywood's lawyers, and it is likely constitutional.
They can't shut somebody up for their opinions. But if you do something illegal or actionable (in this case, contributory copyright infringement), you may prefer shutting up to accepting the full legal consequences of your actions.
They can't shut somebody up for their opinions. But if you do something illegal or actionable (in this case, contributory copyright infringement), you may prefer shutting up to accepting the full legal consequences of your actions.