Hm, I guess I haven’t quite got my meaning across. Let me try again.
You gave what you described as an example (explaining who Neil DeGrasse Tyson or Barack Obama is to an antebellum slave-owner, and expecting to have difficulty doing so, due to the latter’s preconceptions making it impossible to understand the simple truth) of a general phenomenon (having difficulty explaining something to someone, due to that person’s preconceptions making it impossible to understand the simple truth).
And I am saying that your purported example is not, in fact, an example of the general phenomenon which are you describing. In the case you provided as an example, the slave-owner would not in fact have difficulty understanding the simple truth.
This should make us (including you!) lower our probability estimate of the purported general phenomenon being a real thing at all.
You also specified a remedy for this purported problem—namely, lying. But if the phenomenon you describe is not real, or if it’s even much more rare that you think it is (as we must surely take seriously as a possibility, given that we have just demonstrated that your ability to recognize a situation as belonging to this class is worse than you thought it to be), then we must also downgrade our estimate of how useful, or how often useful, the proposed remedy is.
In short, my comment is not some sort of “critically appraising a finger” nitpick. It is directly relevant to the core question of whether your characterization of this aspect of reality is accurate, and whether your suggested actions are appropriate.
I read your comment several times, and looked up some Wikipedia articles about this (fascinating!) taxonomic fact (which I appreciate you noting).
However, I don’t actually see how what you wrote disagrees with what Zack wrote? (Or was that not your intention?)