Not technically but practically. The decrees are effectively considered law by the executive. Yes, you'll likely win in court later on, but you'll lose your job, get sent to prison, have your bank accounts and vehicle seized, etc., in the meantime.
Legality isn't really of much practical concern anymore. It's about what gets/can be enforced immediately.
What a weird comment. How many private business managers have ever been sent to prison for violating an EO? This particular EO doesn't even mention any criminal penalties.