That's a surprisingly arrogant and troll-tier comment. If you don't like it, can't you just turn it off, or write your own editor (which Rob Pike has done at least twice)?

Does Rob Pike also eschew error messages which point out the error's line number as a crutch for weak-minded coders? Does he avoid modern plotting software, opting instead to parse vast monochrome tables of numbers the way god intended? Does he oppose multiple virtual desktops, window systems, and GUIs in general because he grew up without these newfangled shortcuts that cause mental decrepitude in kids these days? He might be a genius who has made an exceptionally positive impact on computing, but he comes off as a bit of a dick in that thread.

Using color to encode meaning is "juvenile" for a reason: it's an efficient way to leverage the builtin pattern recognition features of the human visual system.