I like how the fact that the author has a direct interest in presenting Giulani as in the wrong is buried in the 7th paragraph. That's kind of a crucial thing to know, and should probably have been put at the front of the article, or at least mentioned with a "Full Disclosure" type clause, indicating that the author is not a neutral observer, but rather party directly involved in the "controversy."
Also the fact that 85% of the taxi drivers refused based on location does not mean they were not guilty of racism. As a New York resident I frankly don't understand why cabbies are allowed to deny you entry to their cab based on the location you want to go to. Sometimes they give me a rationale like they are about to go off duty and are trying to squeeze in one more fare on their way back to where they park the cab (which still seems like it violates the "Passenger's Bill of Rights" prominently displayed in every cab which explicitly states that the driver has no right to refuse to take you anywhere in the 5 boroughs). Other times they simply don't want to go where you're going.
I'd imagine that the latter was very often the case in 85% of cases where cabbies didn't want to go where their black passengers were going; there is probably some mix of both racism, fear and profit in making cabbies in, say, Manhattan want to take a fare out to Brooklyn or the Bronx or up to Harlem, but at any rate, they took the job as a medallion cabbie, which entails taking a passenger anywhere they want to go in New York. If they were breaking the rules for whatever reason, disciplinary action seems warranted. If it was racially motivated, then it seems particularly reprehensible. And it's not exactly as if blacks in New York City represent some sort of oligarchy that can push around the Mayor to do whatever they want.
In short, this article seems both unconvincing and obviously biased in both who wrote it and how that information is disclosed.