About a year ago I embarked on creating a color scheme for a project and I loved it so much I began using it for everything. I decided to make an official repo for it to share with the world.
Anyhoo, hope y'all enjoy it.
Problem is, it makes everything super fugly and eye-straining for everyone else (considering no dark reader allowed anymore). And it's much harder to see which parts are important and which aren't. Because everything is super bold and screamy. I didn't buy a 4.7 million colour display to only show 10 of them. I tend to get headaches from really high contrast, I prefer using a softer theme like solarized.
The 0.5% of employees with vision issues would be equally well served with a browser plugin that adjusts it for their particular issue. Not everyone with visual difficulties has the same issue, after all. Some people can't see certain colour combinations so they need to be avoided or modified. Some just see blurry so they need large fonts but probably even larger than they are now. Some can't see at all and they're not helped by this either, they just need a braille ruler and good alt tags on images. Which is something nobody in the company seems to care about. They just care about things that are super noticeable.
We used to have a nice gentle email signature that is now all kindergarten colours and huge fonts and it's just so in your face. For something that nobody ever reads anyway. It was de-emphasised for a reason, so people know it's there but that it's not important information unless you're really looking for it. If you really want to read it you can always just highlight it. Or switch to plain text mode.
Ps: I'm not against catering for disabilities at all, but I'd like to see a more tailored approach. Not trying to fix one thing and breaking it for everyone else. I don't set my phone on huge text mode either but I'm happy it's there for people that do need it.
I agree that local settings should override. But lets start with something legible and override with finely-graduated pastels, not the other way around (as part of a wider push towards good UX defaults).
(Using a high contrast dark mode with small text over here. It's what works for me, and "you can't configure your own environment because security" would have me kicking and screaming like a toddler).
Addressing an issue that affects 10% of a particular demographic (especially when that demographic is over represented on the internet in general) is wise, but the answer is not just “choose better colours” because of the many different forms of colourblindness.
The answer is choosing sensible defaults (stick to frequently used patterns your users have encountered before), support with high-contrast iconography and shape where possible, and don’t rely on colour alone for any part of your design (use tools like https://www.toptal.com/designers/colorfilter to see how your design survives through colourblind eyes).
Anyway, my main point is that although I'm technically colour blind, unless you're using particularly muddy shades of red and green, or particularly small splashes of colour, it doesn't matter too much. The key goal is to avoid colour-dependent design, but not to be afraid of colour either.