I think the point is, as several people have said, that it's not the money, it's that Glocks are more or less fungible. If you tossed your G23 in a pile of other used G23's, for all practical purposes it doesn't matter all that much whether you get yours back out or not.
I know that my dad's (previously his dad's) Belgian A5 is probably not worth that much more than purchase price of a new Glock, but I'd be MUCH more upset to lose that. It's put venison and pheasants on the table for 4 generations. I'd have to scrimp and save to replace that or a Glock with same, but the replacement Glock would be just as good to me as the one lost. A new to me used A5 would not. To a lesser degree, I think there are a lot of guns out there that get purchased for more than empirical reasons. 1911's, for example... I love them, but I'll readily admit that if I were a robot, I'd probably carry something else. And these guns lend themselves to sentimental value or attachment to this particular one.
Lots of things follow this model. I will cry less, for example, over a nice carbon fiber bicycle that gets wrecked/stolen vs a custom steel bike that costs the same. Not that it's ever a possibility in my lifetime, but if a tree falls on my garage that I have a Lexus LFA and a real, original Shelby Cobra in, which half do I want the tree to crush?
Fungibility is the issue here, not value. I'd not be so flippant over the loss of $500 worth of anything, but to each his own.
