Stating that a fire was hot (DUH!) and that it was a result of negligence is a report based on (I would hope) reputable sources and constitutes news, IF true. Speculating on the causes or the source of the aforementioned negligence would constitute commentary as long as you're not taking sides for or against anyone. Stating that the negligence was inexcusable goes beyond merely commenting on events and enters the land of offering a definitive judgement which, if not supported by the facts, could lead to a defamation law suit against a person who says that. I suppose it qualifies as commentary, but it's both wreckless and constitutes advocacy.
But none of that changes the fact that Hannity makes no pretense to being objective. Commentary without at least the appearance of impartiality goes beyond being merely observational in nature. And once you continuously take one side in an argument, you are no longer merely commenting on events, you're taking sides.
The statement you reference ("Have you no sense of decency, sir, at long last?") as having been made by Edward R. Murrow was actually made by Joseph N. Welch who actually said the following:
"At long last, have you left no sense of decency?"