The ISO was merely made for convenience, and for those without the basic technical knowledge required to perform a manual amelioration. Also, Microsoft already tried without success to shut it down in the past, after Linus made a video on Windows Ameliorated.

There is detailed documentation for performing a manual amelioration, it uses fully open-source scripts. (https://wiki.ameliorated.info/doku.php?id=documentation_21h1)