There's an irony in this fragment. One of his guests says that there have not been double-blind randomized controlled trials of the benefits of mask wearing (because it's hard to be blind to the fact of wearing a mask); and yet they have been mandated because of the "precautionary principle" (not sure what that is). Then he says that there has been a trial in Denmark that has shown no statistically significant difference of wearing masks over not wearing them. While I have no idea whether there really was such a trial and whether it actually concluded what the guest claims it did, I remembered how vehemently Bret and Heather defended the common-sense self-evident truth that masks must be effective. This time, however, Bret didn't even object; just nodded sagely. His pet project is now ivermectin rather than bandannas or masks.
If one ignores the appallingly clickbaity title of the video, or how much of a fuss Bret makes in the beginning about how he takes ivermectin, it is actually not a bad conversation.