This is meta communication - communicating about communication. In a complex world it is important to understand when and why communication fails.

I feel that it is important to accept that some things are hard to talk about, and it is important to understand why those things are hard to talk about.

It is hard to communicate rationally while the fight or flight response is engaged. It is hard to communicate rationally to people who either explicitly want to hurt you or who don't mind if you are harmed.

That quote is consistent with what I wrote. If a quarrel (or a physical fight) breaks out over a discussion about a fact then it’s likely that the parties involved with the quarrel aren’t accepting the fact as “bare” (per the meaning I take from OP’s comment). That is to say, they implicitly or explicitly include the “that’s good” or “that’s bad” qualifier alongside the fact rather than accepting it as a “bare” statement of fact.