It only does that for end users who don't want to run the commands necessary to turn all that off. It's mildly annoying, but it doesn't restrict what I as a dev can do with my Macs.
Long link below. That seems to be the current one. It shows how to enable non-App Store applications by identified developers, and also how to open applications it can't verify (I rarely run into this, but occasionally with open source software or niche tabletop gaming software).
