No, it's not warranted. It's a sign of an immature industry. The notion that if a game is announced it'll lead to constant questions or harassment from fans is baseless. A very, very small minority of fans would act that way.
The overwhelming majority of gamers would like to know if there's going to be another entry in their favourite series. You don't need to give out all the details mechanics, etc, because obviously things change.
But I find it bizarre that it's still a mystery whether another, say, Splinter Cell or Bioshock is in development.