I feel a lot like they developed an habit of asking random people in the US government for opinions. They can serve them as "anonymous person from US intelligence" anyway.
Someone doesn't have relevant knowledge just because he is in an institution. DoD, DIA, CIA, etc produce gajillion documents about gajillion different topics. Unless a person is in a team focusing on China, he/she wouldn't know anything beyond a random person from the street. Similarly, even if he is in a China related team, his team might not be about a military topic or cover topics related to submarines. In these cases, unless the said person had used his clearance to learn about Chinese submarines by his own choice, he wouldn't know. Of course, that assumes he has a good enough clearance in the first place.
So, articles that involve anonymous officials are in "opinion discarded" territory for me. Not only it is so easy to lie that way, I need a reason for why I should listen to some govt official about the Chinese military. What is he/she exactly doing in the government besides giving anonymous interviews?