The problem is contrast, really. Some color combos are terrible, and you also have issues with color-blindness (which is why gray is used a lot).
Gray text, against a gray background, can suck.
I’m getting on in years, and low-contrast text affects me a lot more, these days, than it used to.
Yeah, nothing like neon green on magenta. So much contrast, my eyes each read their own line... ZX Spectrum had some excellent color combinations