My point is that it is for the consumer to decide that the statements aren't equal, not the reporters.
His affiliation is relevant in the sense that, when it comes to journalism, it is tradition to allow the "other side" the chance to respond, and give voice to their response. Again, that's why Fox News has liberals like Juan Williams and Jessica Tarlov on staff; they are routinely on panel discussions during "straight news" and even opinion shows to ensure that the "other side" can still have their say. The same is true, I'm told, of CNN.
If you're quoting a partisan tax collector, I would say that there is an obligation to ensure that somewhere in your article, a statement from the other side of the argument is quoted, or at least that a good faith attempt was made to secure one. If Randolph were both non-partisan and had no history of serving in or running for the legislature as a partisan, I would argue that this obligation is not as pressing.
Obviously Democrats can say true things and Republicans can say false things. The same applies in reverse. It's important, however, when presenting one of them that you at least allow the other side the chance to respond. Then the consumer can make their own informed decision as to how to view the matter.