Whatever our biases are, they're not strongly ideological. I know this won't persuade anyone, but the reason is that after slogging through hundreds of thousands of internet comments, one's only response to what people call their "opinions" is exhaustion. It's as if someone has sandblasted the inside of your brain. The result is tedium, except that word doesn't convey how deep it goes. Imagine an existential void of pure tedium, tedium all around, nothing but tedium—then repeat that phrase a thousand times, and that'll be how we feel about these arguments.
HN moderation isn't about suppressing opinions, though commenters who get moderated sometimes feel like it must be. It's about damping repetition in the faint hope of mitigating tedium. I believe that serves the community, because most people don't come here for rehashes of flamewars. They come for something less predictable.