I get where the author is coming from but I think they are conflating quality aspects of an OSS project (readability, maintainability, whether or not it builds

I get where the author is coming from but I think they are conflating quality aspects of an OSS project (readability, maintainability, whether or not it builds on your machine) with aspects that make it Free Software or not. You should evaluate projects for quality, but projects with low quality aren't any less Free -- you can do what you wish with them at your own risk with no warranty.