The mayor is the first person quoted in the story. It's the statement/reason he included with the bill. Who else should we have contacted? The city council? Check. Other municipalities? Check. Government transparency experts? Check. 
So how is this a hatchet job? The city attorney billed Langley for responding to a reporter's question (he declined the request in an email ) and the mayor — the manager at city hall —sent the bill to the newspaper. The people/sources in the story were all explained the circumstances and they responded with their opinions. 
“…I can’t think of any circumstance when the news media would have to pay for any city staff’s time, whether they’re contracted staff or in-house staff.” — Toby Nixon.
"Thomas Gill and Rene Neff both said billing reporters for time spent speaking to a city employee, even a contracted one, was inappropriate and that they believe the issue should be discussed by the entire council." 
So again, where's the hatchet job?