macOS unable to open any non-Apple application

You've got to be kidding me. When Apple's servers are down, all Macs worldwide start freezing randomly? My XCode is hanging during builds, is this why?

This code signing enforcement stuff has gone way too far. Heads should roll for this.

Wait what happens if you don't have an internet connection? Can Macs not be used offline any more, surely that's still a relatively common use case for a laptop even today in a lot of places?

My understanding is that if you're offline, it skips this check and everything works fine. The reason this is a big deal is that the problem's on their end, so you're not offline, so it keeps trying and waiting instead of just letting you skip the check.

Unfortunately there’s not a way to differentiate “we’re online but Apple’s servers are having issues — probably fine” and “we’re online and something something is preventing us from talking to them — something nefarious might be happening.”

Local copy of whatever Apple is checking? Update that daily (on sign on or something). Not going to catch zero day type stuff, but better than making the laptop unusable.

I think the point is that that database is too large to store on a single machine which is why it has to be ad-hoc queried and cached. I mean it will have the signature of every program run on a Mac.