I can't stand syntax highlighting. I mean literally -- I can't read code that is displayed using syntax highlighting, and when someone tries to force me to, I can't understand it. When someone ask for my help with a piece of code, I have to ask them to turn the highlighting off (which in some editors is harder than you think). I normally use acme, which doesn't even have syntax highlighting, but it bothers me to no end that on some (many? all?) Linux distributions vim comes by default with syntax highlighting on. Fortunately BSDs come with nvi, which also doesn't have syntax highlighting.
Unfortunately, most blog posts and documentation on web sites spam syntax highlighting in my face. For those cases I copy the code in my editor to read it which also has the benefit of allowing me to see it with proportional fonts. I use proportional fonts for my programming.
I don't know, I don't think so. I am very sensitive to the color and quality of light, for example I imediately see the metameric failure caused by crappy (99%) of LED lights and I spent months finding some good LED-based lightbulbs.
One hypothesis that I came out with might be that advertising competes for my attention using lots of colors, and I have become very experienced in tuning out any kind of advertising. I don't consciously associate colored text with advertising, but for whatever reason the mechanism seems to be active in my brain.
Sometimes color highlighting actually serves as an objectively beneficial function, for example colored grep output or colored diff output. Even in those cases I still have to turn colors off, otherwise I simply skip past the important bits of the text that are highlighted.
Unfortunately, most blog posts and documentation on web sites spam syntax highlighting in my face. For those cases I copy the code in my editor to read it which also has the benefit of allowing me to see it with proportional fonts. I use proportional fonts for my programming.