Though it might come across as 'dealing in absolutes,' Zed is making the broader point that when one starts learning programming, it's not good to put any book on a pedestal and blindly follow their style - without working through the code.
It's similar to literature where people tend to ascribe the word 'classic' and yet rarely bother to read, understand or appreciate them.
Your example of unsafe functions might work for you but might not be the best example in a book which is being revered as "the classic book on C" and which influenced almost every major language and book thereafter.
I agree - that's why I started by saying that Zed is right to point them out, as I realise that he is teaching people new to C (and potentially to programming). I added my caveats just to point out to the slightly more experienced programmers here that it's not quite the whole story.
It's similar to literature where people tend to ascribe the word 'classic' and yet rarely bother to read, understand or appreciate them.
Your example of unsafe functions might work for you but might not be the best example in a book which is being revered as "the classic book on C" and which influenced almost every major language and book thereafter.