This. So often features to use system colors can cause apps to be unreadable or just look like crap. The first time I get a bug report that people can't read something I will lock the colors the down, I just don't have time for that.

Who says the system theme is well designed at all? Back in the 1980s you could count on most text color combinations on a Commodore 64 or an IBM 3279 or a PC with a CGA working.

Today it is absolutely normal to type

   ls

on a Linux machine out of the box and if you are running X or Wayland some of the file names are dark blue on a black background and completely un-readable. To be fair, if you are logging into a Linux machine on Windows with ssh on CMD.EXE or most terminal software you get similarly poorly chosen colors. (To be fair, MacOS does do better!)

As a web developer it pisses me off because I am expected to follow

https://www.w3.org/WAI/standards-guidelines/wcag/

and regularly my management gets legalistic looking documents from customers complaining that we only have 6.5:1 contrast on something and you know what I do... I fix it. I wouldn't send anything to my tester that was unreadable and if I did I'd expect her to put in a ticket and I would... fix it. When MUI computes the coordinates wrong and something draws 20px right of where it should be... I fix it.

Whenever I've put similar tickets to the various parts of the Linux desktop mafia they close it as "won't fix" and often give me a helping of verbal abuse. Even Microsoft occasionally fixes something (even if half a decade late) and their people are polite.