The thing is, we live in a legal environment where she probably could go to HR and get him moved or fired for saying this. And yet, some men are still sexist jerks to women in the workplace. This suggests that all the blog-posting and HN-comment-hand-wringing in the world won't make a bit of difference.
Don't lighten up—accept. When being able to fire a guy for commenting on a woman's dress doesn't even do the job, no amount of complaining will stop the behavior you deplore.
N.B. I expect this comment to be unpopular, which underscores my point. We (a) live in an environment where an essay like the OP gets upvoted and elicits sympathy from a bunch of mostly technical guys, (b) where women endure sexist comments from a bunch of mostly technical guys, and (c) a comment noting the contradiction inherent in (a) and (b) gets downvoted by a bunch of mostly technical guys. The problem is basically unfixable, at least by the suggested means; shooting the messenger won't help.