24 hour news cycle. Gotta fill the time, and any shred of anything information-like helps add to the discussion.
Every time something happens, the networks fall over themselves to get out the new thing first, and inevitably fuck it up. Recall the Obamacare ruling, and how several networks reported it'd been overturned because they couldn't take the ten minutes to read more carefully.
Putting the information out there isn't the problem. It's reporting it as fact that causes problems. I was watching the BBC coverage of the shooting and pretty much everything new they reported was prefaced that it was speculation, picked up from a US network, or leaked to another network by an unknown source. They were able to fill without stating untruths as fact.
Of course they have logical reasons for acting unethically, just as a common thief has a logical motive for snatching purses. That doesn't make the behavior any less unethical.
A journalist with any shred of integrity should do the same.