Also, this is yet another example of you saying things that are almost totally wrong, without any supporting evidence, and without even the intellectual curiosity to check. Yes, people do, in fact, say it. Though I'll concede that you were only "almost" totally wrong. The phrase, widely used (Google is your friend), is, "if you can't explain it to a six year old..." Attributed to Einstein himself.

Searches for "if you can't explain it to a sixth-grader..." came up empty (well, actually they came up with a bunch of results for the six-year-old quote).

I wonder, do you ever reach a point where you acknowledge that you're wrong? Or will you just hand-wave this away too?