These things actually are important, because regular people do have strong feelings about them, but they matter to elites only to the extent that they can be used to gin up votes without having to dissent on any of the things that they all agree on: killing lots of foreigners with expensive weapons systems, preventing anything resembling a realistic safety net, pro-capital/anti-labor tax and immigration policies, unlimited dark money in politics, etc.
First-past-the-post systems like the US make this particularly easy, since third parties have no chance. If policies like universal healthcare and non-interventionist foreign policy are simply never adopted by either party, voters are forced to make their voting choice based on things that at least are different between the two parties, and elites have arranged for these to be things that barely matter to them at all. They don't have to interact with our barely-there social safety net, worry about health insurance, send their sons to die in foreign wars, or tolerate any of the daily parade of indignities that constitute life for working people.
In short, it's good strategy to manipulate the poors with cheap rhetoric about the 2nd amendment, so that you don't have to have messy debates about expensive things the elites oppose, like universal healthcare.
And this isn't a one side or the other thing. Division benefits both sides, and so playing up to their villainy works in a nice symbiotic relationship. Both sides in office are playing the exact same game, and they play it very well. There was an email from the DNC leaks from Bill Ivey, former chairman of the national endowment for the arts, to John Podesta [1]. I think he phrased things quite succinctly, "We've all been quite content to demean government, drop civics and in general conspire to produce an unaware and compliant citizenry. The unawareness remains strong but compliance is obviously fading rapidly. This problem demands some serious, serious thinking - and not just poll driven, demographically-inspired messaging.".
How many people voted for Clinton thinking, "Yes - I think this politician is somebody that stands for what I truly value and will make a very good president." How many people voted for her because the alternative was completely unthinkable? And similarly for Trump voters. It's not really a conspiracy so much as the fact that politicians obviously have massive full time teams working to min-max elections, and it turns out that getting people really pissed at each other is apparently one of the best ways to do that.
[1] - https://wikileaks.org/podesta-emails/emailid/3599