On the first part: I personally sit somewhat to the right (ie Hayekian) economically, and I find hysterical leftist social campaigns tiresome and annoying.
But HackerNews is a place I come for respite from that, and where I feel most likely to see discussions conducted with a sincere intent by participants to transcend political biases and seek the truth in any issue.
The bias I do see on HN is towards materialist reductionist positions on science, particularly medicine, but I see that throughout society, largely independent of political ideology.
But to the original point, I'm guessing what Dan meant is that the front page won't be filled with articles like this because they don't fit the guidelines:
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Articles that fall outside that get flagged for being irrelevant, or ignored for being uninteresting. I suspect the latter happened in this case.