I think we're maybe talking past each other with definitions.
I think something is a lie when somebody intentionally tries to mislead (even when communicating "facts" if the intent is to maliciously shape the recipient mind). I think when they intentionally try to convey the "right" ideas (as I think this author is doing -- again, using words the way you think most of your peers use them is usually a good thing), that's not a lie. There are gray areas in between. I don't think this is a gray area, except insofar as I don't know all the facts perfectly.
You still seem to disagree with me though. I'd really like to understand why. I have a couple theories, which I'll list, but I'm interested in any insights you have:
1. You disagree with my description of what "lying" is.
2. You think the author is less deserving of trust than I do (since they seem to be profiting almost nothing other than a tiny bit of publicity, since they did outline in their README exactly what they meant, with photos, and since the title didn't stoop to clickbait, my default position is that they likely weren't too malicious, but you might have different priors and might also disagree with my opinions of those conflicts of interest).
> the whole point of overhead ...
That's perhaps the last pertinent thing we disagree about. I'll throw out my opinion, and I sincerely want to know your thoughts on the matter:
An extremely commonplace occurrence is that something is slow and you want to speed it up (measuring perceived latency). If you can magically do that by adding parallelism then it's a good day at work. Unfortunately, parallelism can easily add "overhead" -- parallelizing small or finely grained problems usually increases wall-clock timing, usually substantially.
In that mode of operation, the whole problem you're trying to solve is reducing a certain latency measurement, making it clear from context what "overhead" means. Other definitions don't even enter into the equation.
Zooming out a bit, I've heard that phrasing a ton of times in many different companies. Sure, it's better if people know to speak more precisely (and I think we're in agreement that a few more performance characteristics would be nice to know here), but it's hard for me to imagine a world were my default perception of somebody is that they're lying when they're using the exact same words and meanings as scores of other good engineers. _Maybe_ they are, but that's by no means my default assumption.