[jeffmcmahan]

> but the post contradicts itself in presenting it as a product of our time.

No. It doesn't. Nope. It presents the phenomenon as something that's always true - recall the discussion of time traveling and meeting the same dynamic with different particulars in each time and place.

Moreover, "the point of this post" is abundantly clear: the more closely your views adhere to the mainstream, the more blind you'll be to the costs of holding opinions outside the mainstream because you don't encounter those costs. It's a good point and not hard to understand.