There is also no way to specify in the contract of the function that it can return null. Blowing up your entire program because it can't parse a URL and returns you a booby-trapped value that blows up your program when you try to use it as an URL is something you should be made explicitly aware of. Right? Although there are docs, of course, but who has time to read them? Or write them, for that matter? For some reason many client programmers are perfectly fine with calling random functions that has names sounding close enough and then expecting those functions to behave the way they expect them to behave, and many library programmers don't bother to document the actual behaviour of their functions because they for some reason believe that descriptive and self-evident (well, self-evident to them) names are enough of documentation.

And you know, I think I can safely bet $5 the way TFA came to be was something like this: the author wrote a code that used URL() with no error recovery-path whatsoever, ran it, and it blew up on that line. The author then rolled its eyes, wrote an (admittedly) ugly try-catch around, and went to write the article complaining about exception.

Now, I can bet another $5 that if URL() returned null what would happen instead would be that the author would write a code that used URL() with no error recovery-path whatsoever, would run it, and it would blow up somewhere down the line, on call to fetch() or something. The author would then ponder the code for several minutes, trying to figure out what exactly fetch() didn't like about the URL it was provided with, find that null came from the call to URL() and add the error recovery there. Crucially, they later would not go and write a article complaining about null returns because they regard it as a completely normal and acceptable behaviour.