Your quote does not support your claim that the comments are for interesting and insightful discussion only. in fact, there are some untold guidelines that you must abide by to not be voted into the grey oblivion. One, as the grandparent found out, is that you must only post things that others to deem beneficial. The only yc-sanctioned method of showing support is to vote up. Another strict one is no humor, even if it adds to the conversation.