In your example "a desire" is unambiguously "the desire of Bob Johnson", but in your initial comment "a desire" is not part of a sentence or even paragraph that

In your example "a desire" is unambiguously "the desire of Bob Johnson", but in your initial comment "a desire" is not part of a sentence or even paragraph that mentions an individual or a group, therefore is likely to make the readers assume the author (in this case you) is the one making the claim (in this case that means assuming you are the one who believes it's the most important document)