The gun lobby exists for two reasons: To promote the financial interests of the firearms industry, and to make Wayne LaPierre and his cronies extremely rich. To these ends, the NRA leadership engages in a nonstop campaign of fearmongering designed to extract as much money as possible from responsible gun owners and others.
Viewed in this context, bloody massacres such as Newtown are not really a bad thing. Such events inevitably lead to a call for stricter gun laws, which allows LaPierre to replenish his bottomless coffers with an amped-up round of Second Amendment fearmongering. The carnage also may lead to a spike in gun sales, as citizens are deluded into thinking that more firepower will keep them safe in this dangerous world.
It’s all quite a racket, but at some point, the public at large may recoil at the senseless violence. We may now be at that point.