I agree that it is written unclearly. One problem is the use of the word “possible” where he means “possibly”, but there are many more badly worded parts. This is what I think he’s saying:

    Many people give up on writing songs before the songs are
    finished because they don’t expect the songs to be good.
    Most people are wrong about this, for one of two
    possible reasons:

    1. they are just being lazy and making up excuses for
       not finishing
    2. they are underestimating the quality of their work
       because they're looking at an unfinished product; if
       they saw how the finished product, they would think
       it’s okay.

    Therefore, you should finish writing your song, even if
    it’s a ‘bad’ song, because in the end, it probably won’t
    be bad after all.

Maybe it's almost a plus that the quote is a bit muddled; I interpreted it in a different way:

Even if it is a bad song, at least you've written a full bad song, which means you may have learned something that may make your next creation better.

Both interpretations are valid, and both reflect something about innovation in general.

Really? Straightforward to me. "Release your projects, because they have more potential than you think."