Earlier quoted context omitted.
I don't think anyone is advocating for comments explaining that $i is a loop index.
I don't think so either. But that's what comes out of Thou Shalt Comment. And yes, I have seen loop index comments. Haven't you? I think we'd both agree if we saw a good comment. I just want to focus on the 'good' part rather than the 'comment' part.
Crap comments warn me ahead of time that I'm dealing with a developer who's either too inexperienced to know how to comment well or too sloppy to do a good job at it and in either case I need to be paying closer attention to their code than I might otherwise.