The brain picks up on remarkably subtle things, especially when you can leverage its huge pattern recognition cores. I like the argument for having less clutter by default (i.e., prioritizing certain kinds of patterns over others), but it's been less than 40 minutes since an obscure syntactic highlighting based on the type of a variable saved me easily 30 seconds of debugging. It was immediately obviously wrong and immediately fixable. And I'm colorblind. I think you're able to use more colors effectively than the author gives you credit for.