I know better than this, truly I do...that being said:
First, my congratulations on the tenor of the discussion and the measured responses of all the participants.
Second, although this really isn't the place to posit such a question, most certainly there have been enough posts about guns, mags, and hunting/shooting to allow for a reasonable discussion in the Cantina.
Third, it is hard NOT to respond with some passion to a question which has historically been offered by people with agendas and pre-conceived answers.
Fourth, in a sense, all the rational and thoughtful responses notwithstanding the answer from most individuals who collect anything they consider of interest or value is "because I like them." One might then explore the reasons for these likes or dislikes.
We give things value; it is part of our nature. In many cases, there are practical and obvious answers to the values we assign; in others, there are not. I won't run through a litany of obscure or commonplace assignments of value, but it is a part of the society of human. One might reasonably suggest that the prehistoric cave paintings in France were the result of some deranged creature who wanted to have more power over others and so invoked the spirits of the animals.
One might suggest that politicians want power and control, or that some police do, or teachers, or nurses and doctors....all viable arguments, but certainly none universally true...or perhaps none even generally true.
The defensive tone of responses to gun ownership--on any level--is a result of a general trend to presume that the control or removal of guns from the hands of individuals will improve our society by removing a threat. Recent laws have been ludicrious, being more directed at the fashion of the gun, rather than the function...but still enough to prompt a threatened response from a large, and socially active, segment of our society.
So? Dunno. I find it unlikely that those who don't understand, WILL understand. I know that all the hunters I hunt with hate causing pain, but have no problem with causing death. An implicit contradiction? Perhaps, but "consistency is the hob-goblin of a small mind." (Samuel Johnson?) We are inconsistent creatures, for all our lofty pretense of rationality.
Whether your initial inquiry was deliberately, or unconsciously, provocative, you may have asked it in the wrong forum. The Cantina is generally populated by thoughtful, respectful folk who move past their first emotional response, and weigh the answer they offer with a real desire to provide information, if not education.
Without denigrating your inquiry, you might well have asked why folks collected Beanie Babies. The response would most like be: I find that they have value to me.
Be well and safe,