This sounds like a complaint about the hacker news title, which should have been written for a general HN audience, not a complaint about the blog post, where it is perfectly clear (for its target audience) that SAT means the boolean satisfiability problem.
Which is the problem if the title of the blog post is intended for a mathematical audience and the title of the HN post is intended for the general HN audience.
As others have pointed out, if this is a blog post for a mathematical audience that understands basic concepts in complexity theory, why bother explaining "Big-O notation is a standard instrument for describing performance of algorithms, as it erases small differences which depend on a particular implementation of the algorithm."
Feels like the audience that this post is directed to is essentially "an earlier version of the author", which, to be fair, is a common mistake. I anticipate the average HN reader should be able to understand this blog post - I know what the boolean satisfiability problem is but have never seen it abbreviated as just "SAT".
Don't mean to be overly harsh toward the author, but a first step in good writing is to define who your audience is.
