Basically I'm afraid the author of this post is a bit of a "careless eager student" archetype who, while generously pointing out the gotchas that to an expert might be second nature, is also introducing unintentional errors that add some confusion right back.
I'm not expert in color, but with anything with soo many layers of abstractions (physical, astronomical, psycological, various models that approximate each), it helps to work symbolically as long as you possibly can so the work can be audited. Trying to correct from the current "baked" state is numerical hell.
But see also :
Which isn't terribly unusual. But if your screen is well calibrated, then no -- the sRGB gradient should by definition be identical. That's literally the specification.
(And it is on my MacBook, as Apple screens tend to be among the most accurate of general consumer screens.)