A good reason to break "Use near-black and near-white instead of pure black and white" for blacks is if the design will be viewed either on a projector, or with an an OLED screen as both will display pure blacks quite pleasingly.
Everything about modern design is "unnatural", this design rule is the "appeal to nature" fallacy manifest.
If you need proof that beautiful things can be black and white: https://gwern.net/
(also, OP blog is _so close_ to pure black and pure white, it's almost imperceptible)
You tend to get a smearing effect, where the pure black parts have a slight delay.
You can see it demonstrated in this video https://youtu.be/eHpLN0rX2DI
OLED has a delay when switching pixels on and off.
That being said, if it's static please offer a "high contrast dark mode".
Nothing looks better (and more battery efficient) than pure black on an OLED.
It also doesn't occur on monitors. White and black on a screen is not pure, screens aren't that good.
"Don't use pure black for text" or "don't use a pure white background" are total myths among designers. You'll never have anything close to a pure color on current display technology.