I don't really see any outrageous, corrupt, or surprising things here. Lobbying and trying to steer the media coverage is what these groups do--both pro-and anti-gun groups do this.
It's all about framing. It could also be presented as one side fighting to preserve your rights and ability to defend yourself against the other side using a tragedy of a mentally ill homicide for its political purpose and to punish everyone by removing their freedoms and rights. That interpretation sounds morally just. Which of these interpretations is "correct" likely comes down to your beliefs about guns.
First, "Say nothing." If media queries persist, go on the "offence, offence, offence". Smear gun-control groups. "Shame them" with statements such as - "How dare you stand on the graves of those children to put forward your political agenda?"
Did you read the article?
Yes. What is so shocking about that? This is exactly what lobbying groups do; they create talking points and try to get those points discussed instead of the points that their opponents are trying to get discussed . I can guarantee you all think tanks (for any cause) and pro gun control groups hold meetings and design media playbooks and soundbites like this too. And like I said, which side of this you find correct depends on how you feel about guns, personal independence/responsibility, and the role of government. Neither side is "right" because this is a complex issue and different people have vastly different preferences and beliefs.
As often as I dislike the writing style or vocabulary of aljazeera journalists. I found this article to be pretty flat and fact based. If what they're saying is true (and past NRA actions seem to substantiate it) than it's quite an eye opener. One group fighting for money, smearing another fighting for lives. It's just morally repugnant.