"We're people just like you. We deserve to know!"
While as a member of the public, I'd certainly like to be alerted and informed of any similar events/disasters/catastrophes heading to planet earth. However, I do somewhat see the rationality and understand why those in power/leadership may not want to do so.
Just as moments in this movie pointed out, when faced with soon certain death, many will engage in behaviours or activities or make decisions that they would not have done if their life remained constant/consistent/continuing. A seemingly innocent mention, but when you allow it to develop further to be a choice enacted on by each and every living human being on this planet... it's a scary thought. Just imagine the horrific acts some would do during their last time on earth.
Kill their boss. Murder their ex's. Rape people they've fancied.
And I don't think there'd be law enforcement to stop them. Cause cops are people too. If they knew they only had a few more days or hours alive, they'd probably wanna spend it either with family and loved ones, or indulging likewise in criminal behaviour.
Those last few days and hours would be absolutely horrific.