Welcome to HackerNews. Please read this: http://ycombinator.com/newswelcome.html

"The most important principle on HN, though, is to make thoughtful comments. Thoughtful in both senses: both civil and substantial."

Yes, that's great, but that's got nothing to do with being constructive. Constructive comments are great, but someone could publish a long and interesting comment criticizing wayland or X11 without suggesting ways to improve. As long as the points are cogent, then the comment should make for worthy material. At no point do such criticisms have to make suggestions on how to improve wayland or X11. Just that they are civil, and substantial. Like you said.

Or maybe you're agreeing with me? It seems strange to redirect me to the newbie guide then.

I took constructive as in constructive to the conversation, not to the person in general.

The definition of constructive is to serve a purpose, whether negative or positive it doesn't matter.

Tell fingerprinter this about being civil.