and I’d say they only really work well for -20 to +0 relative to the designers, with a somewhat wider range for teams.

I read this as:「These feeble minds cannot possibly measure my intelligence ! It's over 9000 !」
This «I am very smart» lad must've received a disappointing score, which I suspect explain a great deal of his rant, humblebrag and all.

That or it is indeed satire (although too much effort as gone into the author's blog, that if is satire it's more sad than funny).