Preppers and survivalists that use it as an analogy for the worst case scenario. If you're ready for the Zompocalypse, you're ready for anything.
Teens and young men whom are either gullible or use the idea as a tool of mental masturbation for their egos.
Just to add to that, the preppers/survivalists also use it as a worst case scenario because it's more politically correct/acceptable than others.
Very few care if you're out shooting zombies (the un-dead kind).
Second, because it's police issue? Do you expect the police to restock your ammunition? If so, I direct you to the aftermath of Hurricane Katrina. The police seized weapons, not distributed ammunition. And worst comes to worst, if you find a (preferably dead) cop with some .40 on him, the pistol is likely still there too. Pick it up then.
1. I can confirm the Glock .40 S&W models as being most failure prone. I've seen them break at the range, more than once. Can't say the same for any other Glock (shameless plugs - or any XD or 1911 for that matter )
The Glock 17/19 is a far better choice as far as Glocks go.
2. This. Seriously re-evaluate after looking at Katrina. Any time you really need them, the police are not going to help, either because they are overwhelmed or because they're interested in "ensuring their safety" and think you are a threat with your gun.