First, a little context. The Post publishes about 100,000 words a day, so things can go wrong. Bias, spin, attitude. Call it what you will, readers can smell it a mile away. There is no benefit to reporters, or the newspaper, from biased reporting, because eventually it damages credibility, which is central to the public's trust of reporters and their employers.
Some bias undoubtedly slips in from time to time, and it is the job of editors to get it out.
Slanting a story is a barrier to informing. A powerful, well-reported news article can be easily undermined when presented with spin or an attitude that distracts readers and makes them think about the reporter rather than the content. A big newspaper like The Post has a readership that amounts, collectively, to the equivalent of the world's most foolproof software system for catching errors. Somebody out there will know when something is factually wrong. Mistakes or omissions need to be corrected, not brushed off.