There's no such thing as a "rational person" devoid of emotional interference. (Arguably, the desire for this rationality is emotional itself.)
I, for one, wouldn't care to own a suicide weapon. I don't believe in God, an afterlife, spirituality, fate, etc. (though I believe in chance more than most). I recognize that my distaste isn't cold, hard and rational - but it's my distaste, and I have no reason to attempt to change it. Objects are no more separate from their existence than people.
Nor do I buy used underwear, no matter how many times they've been bleached and washed. Hey, they're good as new, right? No thanks, not for me.
An object that, in the abstract, may have been used to kill? Don't carry. Kinda happy that my Mosin-Nagant might have killed a Nazi, really.