Cannot use type Person as publisher on schema

According to schema.org, a publisher property can be filled with either Organization or Person type. However when I was trying to use Person type on this web’s schema, the Google’s structured data testing tool said it was invalid. Therefore, I can only use Organization type for a publisher, which I opted out later and just use author property. This could be either schema.org who needs to fix the documentation, or Google who needs to fix the testing tool hmmm…