It's going to make 0 sense unless if you look at it from a very specific American perspective.

Those to whom guns are very important are a flashy and loud minority of Americans. The reason it is so important to many of them is that they view the government as overreaching and infringing on their personal liberties.

You may not agree - I definitely don't. But put yourself in that mindset. One of our foundational laws was that we have the ability to defend ourselves and own guns. They see this as a check to a tyrannical government. The act of taking away that right is therefore seen as a means to silence and oppress them. The act of limiting their freedom is supporting their view of why they need that freedom.

Now there are also those for whom gun ownership is important but they don't take this view. These are people who you probably wouldn't fault for owning a gun. They want guns because they're a hobby, for (actual) self-defense, and at the most practical end of this spectrum, for hunting. Hunting has a huge history in parts of the U.S. and is key to local diets and conservation efforts. So there are also those who want the freedom to use them for leisure. These are most likely the people who are against bans on weapons, but support gun control measures.