I think the examples you name aren't what pg has in mind. It's more like saying "God doesn't exist" in the year 1800. It was highly taboo to say something like

I think the examples you name aren't what pg has in mind. It's more like saying "God doesn't exist" in the year 1800. It was highly taboo to say something like this, and doing so would immediately damage your social standing. The other point is: he doesn't argue one should ignore expert opinions in general. He just says that what is sayable in public likely has important blindspots, to which any expert is subject to as well.