I think he means that in the code you'll want to use " rather than ”. ” often end up happening when copy pasting code from some websites or apps like Word and they often cause trouble because they are not parsed as quote characters by compilers/interpreters.

Those people will notice when their compiler complains and will hopefully know better than to copy+paste something from an untrusted website next time.

This code is very obviously just illustrating a point to the people reading it, it seems unlikely that anyone would want to copy and paste it. Lots of code snippets are incorrect code. For example, I often write C code like this:

    int x = ...;

The line contains a syntax error, but I’m communicating to the people reading that x is initialized to some value.

If you understand what the quotes are supposed to be, what is the problem?