I guess a cynical view (and probably that espoused by the article, which I haven't yet read) is that they're trying to normalize the presence of weaponry in popular fiction as well as in everyday social discourse. If you're in the gun business, you don't want the only people talking about guns to be your critics.

The military also has a stake in glamorizing weaponry and warfighting, and they definitely have a symbiotic relationship with Hollywood in that respect.

That'd be like trying to "normalize" the presence of shirts, or automobiles. Guns have been ubiquitous in popular fiction of all kinds for decades, if not centuries, since they're such a useful device for drama or just entertaining fights. Don't forget how Dr. Watson always had his trusty pistol at hand whenever Holmes needed him.

While I generally agree with your point, you also probably know what guns James Bond, Al Pacino in Scarface, Dirty Harry, and De Niro in Taxi Driver all shot.