Nah mate. When a company isn't paying me, I am unrestrictedly free to be objective.
The problem, with companies (and with mafia, etc) starts once you take the money.
So, from that perspective, what you read from most of us, is more objective than anything you read on your internal mailing lists.
We, unlike your HR, don't care about morale, perception and corporate tracking pixels of stuff one isn't supposed to see or read.
HN crowd for the most part are smart and informed people. So, don't look at it as bias, look at it as assessment.