If you really want to understand their perspective, consider an analogous argument involving some other fundamental human right, ideally one that you strongly support.
An easy one is free speech. Many countries without this right believe it is dangerous and stupid, using a litany of rational assertions and examples to justify themselves.
Consider all of the harm caused by people spreading lies and propaganda. The right to free speech ensures the most evil ideas and people can utilize our most powerful social constructs to attack the very foundations that a stable society depends on. etc…
Every right can be abused, and likewise an argument can be formulated against them based on their potential for abuse. Those that support some right typically believe the benefits outweigh the costs.
Hope this helps.
I’m not trying to argue with you.
It seemed that you were trying to make sense of the gun nut mindset. Gun nuts do indeed think firearm ownership is a fundamental human right, so considering it as such is necessary to understand their perspective.