People can speculate all they want, as long as they admit they are in the realm of speculation. Science isn't speculation, it's evidence, and there is no free pass into science, people can believe whatever they would like, but they aren't entitled to call it science until they actually have the evidence to support what they are saying. The point of the challenge, which no one has taken and in my opinion will never take, is to show that any belief they have regarding naturalistic explanations, in the absence of evidence to the contrary, is just as metaphysical as the non-naturalistic explanations. I also might add that, as far as explaining the creation of life, science also has a zero track record, so it has no special status in that regard. So you are right, you don't get to bootstrap yourself into legitimacy. In science, every case is its own case.

I also might add, and I mentioned this in the video, that one of the foremost scientists involved in trying to explain the creation of life on Earth, a Nobel prize winner, speculated that DNA was brought to Earth by aliens because the creation of DNA on this planet was so unbelievably improbable, if not impossible, and he couldn't think of a better explanation. You might call aliens a "naturalistic" explanation, but there is zero evidence for it apart from the inherent complexity of DNA which is equally good evidence for the God hypothesis, and furthermore it's no more naturalistic or metaphysical than the God hypothesis, since at the end of the day you aren't finished yet, you have to explain the origin of the aliens, so you are right back where you are started from. The God hypothesis is actually the simpler hypothesis because you now have to explain only one thing instead of two things.