There's a hardcoded stripping of Unix-style line endings inside:

$userInput = trim( $userInput, "\n" );

Of course this doesn't work properly when input is received from a Windows command prompt, because line endings are "\r\n" there.

On Windows you will get this message ater specifying y(es) to all questions the script asks you:

The role wasn't added because you didn't choose any group to assign.