That's exactly what I'm confused about, where is the slippery slope? It's an extra step in your build process–an annoyance, not a slope. It's like if there was a requirement that macOS would not run binaries unless you stuck "APPLEISCOOL" at the front of all your binaries.
The slippery slope is at the point where a few years ago you could run any application you wanted, then you started getting some scary messages for unsigned applications but still could run applications, then you had to work around the scary messages and now you cannot run unsigned applications.
As far as I understand, there are (surprisingly many) different code paths in the operating system based on whether a binary is signed or not and I would guess that Apple no longer wants to keep around the one where unsigned binaries are a thing.
