Hatefacts are true things (typically unflattering statistics about minority/nonwhite/non-straight/etc. groups) that you’re not allowed to believe are true, lest you be branded some kind of hateful hate-filled person and shut out of polite society.
There is a temptation to utter hatefacts just to show how absurd political correctness can be and therefore how clever and brave you are for uttering them. Some people (e.g. Steve Sailer) make a living doing essentially this.
I am not impressed with this schtick. For one thing, hatefact-utterers usually don’t have either the brains or the nerve to suggest what society should do with the information they’ve so cleverly and bravely provided. (With Sailer it’s nerve.) For another thing, in the rare case where they do make such a suggestion, it is always something that almost nobody would want, sometimes not even something they themselves would want. Or just something immoral, impractical, unthinkable, or some combination of these.
In some ways hatefacts are very much like those facts I wrote about before, whose purpose is to make you feel small and insignificant. Yes, all of human history is but the final blip on the timeline of the universe.
But so what?