> PG opened a pandora's box when he said that downvotes were acceptable when you merely disagreed with someone, instead of doing so for civility. There is no end of sadness and bullshit caused by that remark.
Since that remark came to my attention, I've put less thought and research into my HN comments.
It only takes a few net down votes to make a comment sufficiently hard to read that it is effectively dead. For example, suppose there is an article about government surveillance, which the article opposes, and the article makes an assertion about the 4th Amendment that is wrong. If you post a comment explaining the error and how the 4th Amendment actually works, some people will misinterpret this as implying that you are in favor of government surveillance, and down vote you for that.
The people who correctly interpret the comment are not as likely to up vote as the people who misinterpret are likely to down vote, and so the down voters have an advantage.
If down voting simply moved the comment toward the bottom, rather than making it almost unreadable, it would be OK. It the combination of making down voted comments hard to read and saying that down votes for disagreement is OK that is the killer. The message that sends is that comments here are supposed to agree with the majority opinion.