People used to get interviewed by people whose ideas they disagreed, or even hated, all the time. When did this become a sign that you were associates or allies?
I think because the point of YouTube is to get more hits for your channel and more subscribers (because that earns you more money) then the benefits of interviews like these are to the host, rather than the guest. If he is notorious for his views then his viewers are very likely to have the same attitudes as he does. So, the benefits would have helped his influence on YouTube.
I've seen interviews like this before (there's another awful Christian fundamentalist who goes onto campuses in the US and holds debates about abortion, rape etc) and I've seen him interview feminists on his channel. He tries to argue with them on air but not that successfully. What he does do is wait until the interview has ended and then, once the guest can no longer reply, sets about ridiculing them and pointing out just how wrong they are.
In this instance I can't see how it benefits the GC argument at all. Either he agrees with what PP says, in which case it looks like the GC argument is part of a wider racist, anti Semitic, misogynistic argument or he disagrees with her and encourages his followers to do the same.
I can't see what a "win" here looks like for PP.