$_ is pronounced "it" and should only be used in small blocks of code. This is in much the same way that in a paragraph of text "it" should only be used for transitory sentences on the same topic as the previous one.
What's wrong to type $_ if you want to print "`$_'\n" in your example? Etc. I don't see any problem with that as $_ is clearly states that's a loop counter. And let's don't even talk about map/grep/sort and schwartzian transform.
I don't think he sees that as a Problem. Only he thinks using it explicitly is not to his taste. I have a similar attitude: make it explicitly a new var if it is going to appear in the code.
