Whether or not the NRA has any real advantage or benefit from engaging in a public debate with the Commander-in-Chief is not really my concern.
When your organization slanders, mocks, ridicules, and insults the President of the United States for 8 years, making completely bogus and baseless claims like, "He's coming to take our guns away" and "He's trying to create a fascist dictatorship by first disarming the populace" - you will accept an opportunity to face the man you have made a smear campaign of, or you will be considered an organization of spineless cowards.
I thought for a long time that, despite the obvious fear-mongering and propaganda-based tactics the NRA uses to spread its message, perhaps they had some reasonable, rational reasons to defend their position, or at least pretended to have, like Christian apologists, but now it seems that I was giving them too much credit.
Political opponents say nasty things about the opposition; this is a fact of life. Before he was even president, Obama was referring to people as "bitter clingers", and his rhetoric has only gotten worse since then - "Terrorists" is one of the nicer things he's called the NRA these past few years. The speech he just gave was full of lies and deceptions, and slandered tens of millions of law abiding gun owners. Do you think he'd agree to a debate run by Fox News at the NRA's annual meeting? (Hint: No)
The NRA has spent decades explaining its positions, and justifying them. Lower crime, self-protection, hunting, competition and fun, and (of course) the Law are just some of those reasons. If you really want to, you can go to their website and read all about what they support and why.
For his part, Obama has declared he doesn't think anyone should be allowed to own a gun. He is on record as repeatedly saying that he wants to pass gun laws like Australia's, where they implemented a nation-wide gun confiscation program. He has gone to little effort to hide his opinions over the years, so don't be surprised when people take him at his word.
It is also true that every dictatorship starts by trying to disarm the populace. I don't recall the NRA ever stating that they seriously believe that Obama intends to overthrow the US government, just like I don't believe Obama seriously thinks that gun owners are actual terrorists for owning guns and not shooting people with them. The term is
rhetoric.
Politicians, of all sorts and parties, are gutless cowards. Their entire job depends on image, so that must take precedence over whatever substance they may have. PR offices are worse, as they don't even pretend have any ideals. I don't expect them to be nice to their opponents, especially when their opponents are attacking them.
If your entire reason for hating a person or an organization, especially one with millions of active members, is that someone said something nasty about someone else, you must also hate the Democrat Party, the Libertarian Party, the Republican Party (those three are 90% of US adults so far), BLM, OWS, TP, NOW, PP, CAIR, CPUSA, oh, just about everyone. Or, you already disliked the NRA for holding a position you didn't agree with and are looking for excuses to justify it.
That is the hardest part about trying to discuss guns over the internet: almost everyone has already made up their mind and just wants to talk. Structured arguments, such as the use of facts and logic to persuade another to your view, are too difficult and take too much time. It's so much easier to jump straight to the attacks, do your virtue signaling, and feel good about yourself and hate your opponents.