An investigation of FOSS development would highlight a bunch of problems that exist to a lesser extent with other software development. When money is on the table and there is no motivation to keep supporting behaviors that particular contributors favor then feedback shift things. When you're building stuff for "yourself" then that feedback doesn't land the same even if the project owner has aspirations for better UX.
... falls flat on it's face in the first impression by looking like an unresponsive window, due to the disorientingly light gray color design choices. I also just tried it and of course it's not notarized, meaning that it's almost impossible for anyone to install on macOS, unless they know of the secret button in System Settings. Nope, they aren't there yet.
I don't understand why you're blaming the Darktable team for that when it's Apple that makes it nearly impossible for anyone to install a program written by someone who doesn't pay them $100/year.