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 Neander...
Another month, another rationality quotes thread. The rules are: