A perfect example is the other poster who basically got called to task by dang for asking for sources to a claim. Dang characterized it as "unsubstantive" and lowering the signal to noise ratio.
For myself, a reasonable discussion is one which it's expected to be asked to cite sources. A community in which not doing so gets you called out.
Discourse on HN is too touchy feely, people are generally afraid to challenge others in a straightforward manner, so they end up using a lot of words to do so. It's like being in that meeting where the manager is using flowery language to extol the virtues of the company, when in reality everyone is there for reasons that don't involve the company itself.
I just kind of tolerate it, but in no way, shape, or form, do I view the discourse on HN as generally being honest or useful.