This is not the developer choosing what software can run on their computer, this is Apple choosing for you and then you having to go disable protections (with what implications?) to then be able to choose what software you run.

This has more to do with putting up a scary dialog for normies than it does protecting anyone. A non-technical user isn't going to go bypass this in the terminal, they're going to run back to the App Store where Apple can collect that sweet 30% and analytics.