>I'm sure people noticed this issue internally and brought it up but some thing by some designer was seen as biblically sacred and overruled all reason.

I disagree. Seems more like the group that implemented border radius at the OS UI implementation level did not work with the group that handles window sizing. Not everything is a conspiracy.

Of course it's not "a conspiracy", but it is a major, gigantic, huge, alarming failure by Apple. Resizing a window is just about the most basic and useful thing a window system can do after opening a window, and Apple totally messed it up. It's like they've never worked with a window before, but TBH though, their window system has always sucked.