At the very least, maybe the Pubs could insist that the moderator explain his political background so that the audience could have a sense of his biases (for instance Matthews being an aide to Tip O’Neal).
The Pub candidates don't have to collectively demand an explanation. What they do need is the ability to think quickly on their feet and when faced with a loaded question, fire back at the moderator. For example:
Candidate John Doe (insert the candidate of your choice): Mr. Matthews, while I am well aware that you were once a top aid to liberal Democrat Congressman Tip O'Neal and expect questions like this, for the sake of our audience, could you at least pretend to be unbiased for a few minutes this evening.
If every Pub candidate gets in Chrissy's face like this, then Chrissy will spend half the evening on the defensive trying to pull his panties out of his butt.