Just because a map is a deathmatch map doesn't mean it has to be too low on contrast and/or uninteresting looking. I would say that the right image is best in many aspects: not only does it look better/more interesting, it also focusses the player on the better-lit floor and ceiling, giving a better sense of direction and allowing players to focus on area's that matter.
However, I do agree no map is the same (hopefully) and that different situations call for different lighting types, but what that article presents are general thumbrules and guidelines to help those that haven't grasped these basics yet. Once you're familiar with the underlying rules, you can decide when it's usefull to cross such a rule. The same goes for vertex manipulation or any other issue: it's a dangerous tool for beginners but usefull once you know how to avoid the trouble it can cause.
At least, that's the way I see it.