This was a Grizzly attack at night... more than likely unavoidable even if armed... since most of us do not post sentry through the late hours. Though a firearm may have saved the life lost, it probably would not have helped avoid this attack.
I guess it would depend on how well you maintain your focus as a 500 lb bear is chewing on your arms... and if you left your gun within arms reach in the tent... and if you can still reach it with bear jaws clamped down on a limb.
This is speculation, but it is highly likely that improperly stored foods lured the bears into the camp... who then got curious about the scents and noises from within the tents.
I never hike without a weapon... but a bear can, proper food sack storage and backcountry experience and know-how can deter a bear attack better than a gun, simply by avoiding the unwanted contact in the first place.
Sadly, Grizzly bears are naturally curious and will eat just about anything... including hikers if they get hungry enough. The article mentions Griz's in our WA forests... but I have yet to see one, or meet anyone who has in the wild in WA. We have black bears here... while still a wild creature and nothing to mess with, as a whole they are far less dangerous than the Griz's