No, that was absolutely not his point. I don’t understand how you could have come away thinking that- literally the entire next paragraph directly stated the exact opposite:
I don’t think that the following classes are the same: (1) Facts everyone should know. (2) Facts everyone knows.
I think the author claims that this is a (1) fact but not a (2) fact.
(a) Everybody knew that different ethnicities had different brain sizes
(b) It was an uncomfortable fact, so nobody talked about it
(c) Now nobody knows that different ethnicities have different brain sizes
I don’t think that the following classes are the same:
(1) Facts everyone should know.
(2) Facts everyone knows.
I think the author claims that this is a (1) fact but not a (2) fact.
His claim was:
(a) Everybody knew that different ethnicities had different brain sizes (b) It was an uncomfortable fact, so nobody talked about it (c) Now nobody knows that different ethnicities have different brain sizes