Point to a single place where the policy even implies that uncomfortable truths are not endorsable?
Like I said, I'm sarcastic - but I definitely have seen HN go downhill since I've been here over the last couple of years. I look at the need to say things more constructively as a learning and growth opportunity.
Uncomfortable truths are uncomfortable. People often confuse discomfort with wrongness.
The policy doesn't have to say that people shouldn't endorse uncomfortable truths for it to have that result. That people will misuse power to keep comfortable is something that you shouldn't have to have explained to you.
However, you've created a false dichotomy; there are things in the world that are neither abusive nor particularly collegial.
The concern is that in getting rid of the abuse, Hacker News will also get rid of uncomfortable truth.