Well, I would say this much. If Ms. Sims is saying that these witnesses actually believe in what she has just said.... You are questioning the credibility of an individual. If you're saying that the quotes they use for stories they write or that the research they do is fundamental to what they believe.... Is that what you are suggesting?
As far as I know, in Canada you can do interviews with those you don't agree with, often to show how good or stupid those ideas are. If you are suggesting that the individual who is going to be the witness believes what you've just said, you are going to have to provide factual evidence of that to this committee, because you are dragging someone's name through the mud. To take it to that level.... If that's what you want to do, that's fine, but you'd better be damn well sure that you have the right evidence in front of you.