You're trying way too hard to make this about bias. There are more charitable and simpler explanations, such as signal-to-noise ratio and the expectation that submissions to HN are focused on geek-oriented science and tech topics.
The reply you are quoting is currently at -3. Voting is more about about affecting visibility than whether one agrees or not. Or ideally should be. Does this tell us something? Doesn't it kind of prove my point for me?
I'm sorry but you're just doubling down on your baseless assertion. Just because you argue everyone might have their personal bias that does not mean that everyone around you is desperately trying to not challenge their beliefs. That's a very specific and very personal interpretation that you're trying to pin on everyone around you without any basis.
Meanwhile, there are simpler and reasonable explanations that you somehow decided to ignore.
As far as I'm concerned that it's downvoted only "proves" that people tend to prefer more substantial conversation than this. If you had posted something of value I wouldn't have downvoted it, even though I probably would have disagreed with it.