I find it odd that they had to preface mentioning the homeowner's weapon with "legally possessed."
It's similar to when I see "fully-loaded." It's superfluous and irrelevant information designed to elicit an emotional response (I suppose). The load condition of a firearm is binary: Loaded vs unloaded. Whether the mag is topped off with one in the chamber or it's loaded with a single round does not change the status or lethality of the firearm.
The same is true with "legally possessed." Does it matter? If it was used in legitimate self-defense, that's pretty much all we need to know. I submit that the possession can be assumed "legal" unless it was ILLEGAL. If it was ILLEGALLY possessed, THEN maybe that information would add some value to the story.
But, otherwise, it's like saying, "He drove his legally possessed car with a current license to the store."