That's easy: respectfully, but directly, bring the disagreement to Randy, along with a clear and sound explanation of the basis for the disagreement.
FlyerTalk is Randy's sandbox, and I am grateful that he allows me to play in it. However, I am here precisely because he's created an amazing on-line community. If he should take a step that, we think, is contrary to best interests of the FlyerTalk community, it is essential that we let him know. And, of course, the fact that there is a TalkBoard at all confirms Randy's desire to receive input from the membership. I've certainly never been shy about communicating my thoughts directly to Randy via PM as a member. There's no reason to be any more reticent as a TalkBoard representative.
TalkBoard shouldn't be (and, I don't think has been) a rubber stamp for Randy, and I sincerely doubt Randy wants it to be.