They’re not even good at being pedantic. It should be ‘"them’ is not singular," with single quotes around ‘them.’ The sentence means to refer to the word itself, not the concept the word points to: Paris is a city in France, but ‘Paris’ has five letters. Philosophers call it the use/mention distinction; getting it right eliminates a lot of confusion when you’re switching between talking about words and talking about concepts.
They’re not even good at being pedantic. It should be ‘"them’ is not singular," with single quotes around ‘them.’ The sentence means to refer to the word itself, not the concept the word points to: Paris is a city in France, but ‘Paris’ has five letters. Philosophers call it the use/mention distinction; getting it right eliminates a lot of confusion when you’re switching between talking about words and talking about concepts.
Ceci n’est pas un pronom.