Generally, mods' goals are something of a dual mandate: intellectual curiosity (see: <>), and trying to keep the discussion from boiling over, which it's constantly on the verge of. I'm not finding the comment I'd had in mind yet, but this one at least hints at the concept: <https://news.ycombinator.com/item?id=32588063>.
And a longer one which goes into the whys and wherefores: <https://news.ycombinator.com/item?id=29803838>.
Another long and good one: <https://news.ycombinator.com/item?id=28176705>.
For clarity: I'm not a mod, I occasionally disagree strongly with mod's positions. But I've also come to understand, if at times grudgingly accept, their principles.
And "just telling the truth" isn't a defence, justification, or excuse.
If you want to explore this issue further, you are free to search though dang's voluminous set of responses on this and other topics.