Who cares what "one person" says? You can find all sorts of nonsense on the web.
If you can't make sense of the library code, and the documentation and examples are insufficient, then look for complete midi projects that use the library, and see what others have done.
If that is still not enough, do the best you can to accomplish some simple, isolated tasks that are just part of the big picture. If you run into trouble with those, post the details on this forum. Or maybe the Adafruit forum.