There’s are two big aspects here actually.

The Godfather series was the authors first ever screenplay. He famously had no idea what he was doing and didn’t really understand the scriptwriting format yet. He has a famous anecdote where after the movies came out he went to try and actually learn how to write a movie and he saw his own work as an example of what to do.

It’s The Godfather Part 2, the sequel to an already successful movie that later became known as one of the best films of all time… There’s a juxtaposition there where it would be expected for there to be mastery involved but the thing above is stating that it was so poorly written that the great story and the success of the previous one wasn’t enough for any studios to want to make it.

However… I think you can safely ignore both as I don’t think the guy who originally made it was thinking more than “damn this is some good kush”