> Dependency Dog: If you want to see a good example of a leaky abstraction, consider AppKit. Not only is AppKit thread-unsafe to the point where many functions can only safely be called on the main() thread, it forces you into Apple’s terrifying Objective-C model. Basically any program that wants to have working GUI on macOS now needs to interface in Apple’s way, with basically no alternatives.

Uhm, every OS that I've developed a GUI for has a similar limitation. The "only call this thing from this thread" is a well-known thread safety pattern. It might not be the pattern that this author prefers, but it is an industry standard pattern for UI.