Most of them are emulating the EGA/VGA palette which was a regression from the CGA terminal colors.
https://int10h.org/blog/2022/06/ibm-5153-color-true-cga-pale...
https://int10h.org/blog/2022/06/ibm-5153-color-true-cga-pale...
Kind of anal about this since I started with a lot of CGA and EGA displays when I was in my late teens and early 20s and relatively involved in the ANSi art scene.
Here's a related project I'm working on for playing doors in a web browser.
They could also have done something about the two magentas though... E.g. made one of them orange?