Hey Marc, I do agree that Swift is (at this moment) an unstable language. But I think you will agree that we got most of the growing pains out during the switch from Swift 2 to Swift 3 back in 2016!
I chose to use Swift instead of Objective-C because this post was geared towards newer developers, and most iOS Devs who have started in the last two to three years use Swift. Apple itself is in the process of porting much of its code over to Swift.
While I am capable of creating frameworks in Objective-C, I am also excited to continue to be part of the Swift Evolution! Besides, if we never try new things, then we would probably still be creating websites with tables, HTTP (instead of HTTPS), and Flash!