They don't remove font smoothing. They switch it from subpixel level to grayscale only. Technically subpixel should produce better results then grayscale. But IMO the subpixel antialiasing in macos looks horrible. So you might not even see the difference as it looks exactly as horrible as before.

I'd be more outraged if Windows removed cleartype, because their subpixel font antialising actually works and is configurable.