Or because it's delivered offensively.

Or because it's phrased tendentiously.

Or because it's irrelevant.

Or because it's false by implicature.

And so on.

For example, the following statement is true:

Human beings have a degree of Neanderthal genetic admixture.

However, if, during an argument about politics and science fiction, this were phrased as:

You are not fully human.

This would be offensive trolling, for all of the above reasons. Especially if the victim were a member of a racial minority historically treated badly. "Haha all I meant was Neanderthal DNA, you hate science," doesn't save the statement, it just extends the troll. This is not because people are upset about an "uncomfortable truth," but because the speaker is being a jackass.

And indeed, that quote is itself trolling. It is a favourite troll tactic to claim to be just a persecuted truth-teller! And surely if you know anything about Vox Day, you would know that he is one of the Internet's leading trolls, who takes great delight in upsetting his ideological enemies, and no, not merely by "speaking truth to power." Which makes me suspicious of your motives in posting this here.