Colours interfere with scannability. It forces you to deal with text one colour region at a time, making it harder to take in the whole thing at once.
Scanning is a skill you acquire with age. As you get older, and you more and more replace word-by-word reading with full-page scanning, colour becomes less attractive.
Less attractive doesn't mean worthless. Colour just needs to carry its weight, by providing enough relevant information to compensate for breaking up scanning flow. So used sparingly, colours can be good.
It's just that no one seems to use colours sparingly. You see things like giving ".gz" (and other compressed) files a different colour. I have no need for that, .gz is just one among a thousand file extensions that I know, I can read the file extension myself thank you very much. Even if I had a great need for recognising compressed files, I couldn't rely on colours for that: Colouring is too inconsistent between applications, whereas scanning text and spotting the .gz extension carries over to almost anything.
I was looking at how my younger colleagues were organising their screens, with IDE tool windows taking up most of it, and leaving no more than about a quarter of the screen to the source code editor, and comparing it to my own workspace, where the source code takes up most of the screen. And it struck me that 25 years ago my workspace looked more like theirs today than mine today. The scanning bit is the explanation I came up with.
Wrt. colour, there's the concept of alarm colours in cognitive psychology. That, at least, should be DDG'able. It's the observation that certain colours, mainly red but also yellow, pull at your attention. This is a hardwired part of human cognition. If there are alarm colours present, then it becomes harder to read the rest of the text, because the alarm colour keeps trying to pull you in.
Scanning is a skill you acquire with age. As you get older, and you more and more replace word-by-word reading with full-page scanning, colour becomes less attractive.
Less attractive doesn't mean worthless. Colour just needs to carry its weight, by providing enough relevant information to compensate for breaking up scanning flow. So used sparingly, colours can be good.
It's just that no one seems to use colours sparingly. You see things like giving ".gz" (and other compressed) files a different colour. I have no need for that, .gz is just one among a thousand file extensions that I know, I can read the file extension myself thank you very much. Even if I had a great need for recognising compressed files, I couldn't rely on colours for that: Colouring is too inconsistent between applications, whereas scanning text and spotting the .gz extension carries over to almost anything.