You put those words in my mouth, buddy. To clarify, social ineptitude combined with a degree of self-assured narcissism, resulting in a total disregard for the opinions of other people which don't jive with the most "logical" worldview. It's possible to be socially introverted and still considerate to other people.
Not the readership - assuming similar statistics to reddit, the vast majority don't comment, so we can't know - but it's certainly reasonable to draw that conclusion about the commenters from the comments on majority of threads regarding social issues.
Of course, there's a feedback loop in that people won't comment where the majority seem to disagree heavily with their morals, so that doesn't help with what threads like these look like. The sheer amount of personal attacks against people who disagree with victim-blaming views of this in this thread serve as a warning not to speak up.
This is pretty accurate, I would not have commented at all in here until I read this and just wanted to back you up on this point.
I read these type of threads on HN constantly and every time I walk away absolutely disgusted with what I see said in them. I don't have the will to comment myself because it just would not change anyones opinion and they would instantly go into attack mode.