macOS unable to open any non-Apple application

Maybe it's just me but the idea that my computer lets Apple (+ any LE organizations) surveil my app launches seems so much scarier than any malware.

Is this the one-time signature checking that has been in place since Catalina, or is this something else? (And if so is there any information about it?)

I experienced the issue with Mojave while this was happening. So not just Catalina.

Ok, but this doesn't answer the question. If this is the same behavior since Mojave, why aren't those users complaining about this outage on their Mojave and Catalina based system?

Presumably something changed, but so far I haven't heard an explanation that makes sense of it.