It certainly would have been more useful if it had a disclaimer at the beginning indicating that it was written by a Passenger developer. It's OK to have biases as long as you're up-front about them.
The "License and price" section at the beginning is also worded in such a way that it should be clear that the text came from the Phusion Passenger authors.
Any reason why you do not keep it with the company repo https://github.com/phusion ?