There is a difference. Producers nowadays know that the internet reaction can't be avoided from the time that you play your first public performance, whether it is out of town, or in NYC. A paying audience member has the right to say whatever they want. A composer who is concerned about work being judged prematurely would be cautious and protective about demo materials being released or heard at all. If an actor talks publicly about their next job, well, surely they know to expect people to talk and report about it.
But feeling like you can announce a closing of a show before the production makes it official should not be in the hands of the general public. BroadwayWorld had every right to delete your thread.
Begin at the beginning and go on till you come to the end: then stop.