Because a shell script is supposed to be a lowest common denominator. Run this, and it'll ensure you have Maven, it'll ensure you have Java 11+, then it'll build the thing and run the thing.

And now I'm needing to sniff your OS, detect whether or not Homebrew is installed, install it if not, then install Bash >3, then run the actual meat of the script.

All because of Apple's lawyers being scared of GPLv3.

At this point, I may as well insist that you install pyenv and Poetry and deliver it as a Python package.