The guy who came up with this also summarized his position on Twitter, and I think he's right:

One side has a deep attachment (individual ownership of weapons qua weapons, unconnected to recreation) they view as healthy, essential, and normal. In their culture, it is normal. The other side sees it as deeply repulsive and shameful. In their culture, it is.

From the link:

The way we got here is simple: each side is trying to destroy the other. You win wars by force. And culture wars are no different. Each side fires their volleys, back and forth.

The NRA allied itself to all kinds of unrelated hot-button issues. New York State passed a 2013 gun ban that achieved 4% compliance and had effects like a father of three facing 15 years in prison for a pistol grip. The NRA made ads that alienated millions of people and ranted absurdly about “the clenched fist of truth”. Massachusetts banned bump stocks and sent a letter to every gun owner in the state saying, “Turn in your bump stocks by February 1, 2018 or face life in prison.”

Round it goes. The gun controllers feel like the gun rights crowd will never give an inch. The gun rights crowd feels personally threatened — “If that father of three is facing 15 years for a pistol grip, I could be next.” And both sides just dig in deeper.

My own experience mirrors this. I'm incredibly moderate on gun control, as is every other gun owner I know. But even the moderates among us are nervous about accepting further restrictions, because we have no reason to trust that this will satisfy those in favor of more control (and vice versa). But I don't want to actively advocating for gun ownership for basically the same reason: there should be more restrictions than there are, but it's all-or-nothing with everyone. When too few are willing to act in good faith, we get, well, the status quo.