Has your 8 yr old really known this for years? He may behave in a conformist way, instinctively, without being able to describe it or understand the phenomenon... both of which are, in my opinion, required to know it.
And who's figuring out whose communication? He basically has to draw a picture in crayon of what he means, just so all the rest of you don't misconstrue his meaning. Your "human communication" is much too defective to be so proud of it.
I assume by "draw a picture in crayon", you mean provide a very simple explanation. You seem to be confusing the fact that children generally draw simple things, and also draw with crayons commonly. But there is nothing about crayons intrinsically that means a crayon drawings must be simple.
Having drawn with crayons, pencils, and pens, I think there is an intrinsic property about crayon drawings that does severely limit their maximum complexity/detail.
If he has to draw a picture in crayon, maybe he must think a little harder with that big head of his about how to say it properly in the first place so it doesn't require a second explanation?
In this case, it's really hard to understand why someone not completely idiotic when it comes to communication would have used the phrase "I like that sentence" after saying "Blacks are more stupid than whites."
And who's figuring out whose communication? He basically has to draw a picture in crayon of what he means, just so all the rest of you don't misconstrue his meaning. Your "human communication" is much too defective to be so proud of it.