I think there’s a reason these posts always end up on programmer focused places on the internet. Yes, I’m sure their job is annoying, and it would be easier to not have to solve time conversion problems, but the time conversion problems wouldn’t even go away if you forced everyone to use UTC. You’d just start having to do conversions to solar time, or looking up waking hours (which is just timezones)
Which is short sighted considering it is much easier to make a standardized library for converting time zones than it is to make a standard library reflecting what different time numbers mean in different places around the world. If they somehow convinced people to make the change, they would find out pretty quickly they were better off with the devil they knew.
I can’t imagine that’s the main reason. You can buy a 3.5" floppy reader with a usb connection for like 20 bucks on amazon and anyone who wanted to get their hands on government secrets would not be deterred by that.
I think the simplest and most likely reason is that updating things and making changes in bureaucracies is hard on its own, and any time you start dealing with tech it’s all a house of cards where one system depends on another and so changing any one thing will either make it all fall down or bring along with it massive sweeping changes.