I suspect the designers with their near white and near black to have superior monitors that are capable of more contrast than regular users. Ironically my cheap monitor automatically converts pure black and white to near.
My understanding is professional designers use color-calibrated monitors, which unfortunately have nothing to do with the actual monitors and screens most people actually use to view content.
Designers monitors' are calibrated to perfectly match a cheap 90s CRT (sRGB, Rec. 709, 200 nits brightness). Sadly, most cheap modern LCD screens are far worse in contrast and color gamut than 90s CRTs.
