Pinker is 68; it was extremely uncommon to use "they" for most of his life. I can completely understand it just sounds "wrong" to him, because it really is quite a radical shift to how the word was used (none of this "it's been in use since the 14th century" bollocks please; it fell out of use since well before Pinker was born – you would be unable to even understand English as spoken in the 14th century because it's a different language – it's a bad faith bullshit argument)
I've been using 'they' as a generic pronoun since before it was cool, but I'm also not a native English speaker and a lot younger. In my native Dutch there isn't really a good equivalent of a gender-neutral 'they', but people have tried to introduce it in recent years and it all just sounds spectacularly wrong to me, because I guess my brain is hard-wired to consider these things wrong.
I think most people that point to the historical use of the singular 'they' aren't trying to make any kind of bad faith argument – I think it's more an attempt to justify the modern usage by pointing to historical precedent as many folks feel that adds legitimacy.
Personally, 'they' singular has sounded natural to me my whole life. How much of that is generational and how much of it is regional variation would be interesting to know.
I've been using 'they' as a generic pronoun since before it was cool, but I'm also not a native English speaker and a lot younger. In my native Dutch there isn't really a good equivalent of a gender-neutral 'they', but people have tried to introduce it in recent years and it all just sounds spectacularly wrong to me, because I guess my brain is hard-wired to consider these things wrong.
Changing language takes time.