Supplying date meta is as basic as having contrast between your font and background and having font set at a legible size. "Because you don't owe it to a reader" does not really make for sound reasoning if you ask me.
The nomenclature of content is mostly irrelevant to this. It doesn't matter what you call it, an essay, article or tutorial. Still benefits from date meta.
Case in point: any luck finding tutorials for say, a recent version of backbone.js? You have to look hard as most of are out of date and even if they are up to date, it's hard to tell (knowing when a piece of content has been updated is just as important).
Hiding the date meta just makes it all the harder and it's reader-hostile. If you are writing about a topic, it's to benefit a person looking into a topic. I think some people are missing the point of creating the content in the first place.
If you want your content to appear valuable vs less valuable, write the hell out of your content. Make it impossible to discount the content by making it stand out.
In science, researchers don't cherry pick and refer studies written in the last 5 years. They go back as far is relevant. They will refer back to hallmark papers regardless how old. Same with nonfiction books. Same with well written blog posts, because good blog authors often cite references to give the proper context. That's kind of the point of blogging, the power of linking and building upon what has already written. But making a piece of content float in some unspecified time vortex disrupts that.
What's more is that a clear date indicates that the author wrote it at a certain time. It makes it harder to distinguish people that copy content or write about similar copycat ideas from their more original authors.
For what it's worth, I'm not against the idea of situating your content in the best way possible. I think using categorization like tutorials/articles/essays is a better way of framing certain types of content. That can help the reader. Hiding the date meta is an attempt to help the author, while hampering the reader. It doesn't even add up.
Point still stands though, are PG's essays devalued because he puts a year date on them? I don't think so.
I would hope that backbone.js releases carry version numbers. As a developer I usually know the versions of the tools I'm working with. But I might not know (and often don't) when exactly they were released.
I happen to agree with the people who are annoyed by the lack of a date. For most technical topics I research, I want to know when the article was written. Even for nontechnical topics, I generally want to know if the article represents the author's current thinking or something more distant.
But I'm not most readers, and like tptacek pointed out I'm certainly not entitled to a date on the post. Since I am unlikely to hire the writer, optimizing for my happiness is not exactly expected here. Of course, if I were to be looking to hire the reader, stale content isn't really going to bother me. It could of course affect if I see the content at all (via a search), which I expect may be one of the larger points here.