You get some points there. But, I'll remain hung on this bit: " I have explained the expansion of the universe to many lay people without trouble."
If you explain something to 100 laymen, and more than 20% actually understand what you are talking about, then all is good. If another 30 or 60% understand parts of what you are talking about, that's good too. And, if I am among the remaining group that didn't understand a damned thing you said - then so be it. I can look around at my fellow laymen, and realize that they probably have more education and expertise in this area than I have.
If, however, less than 1% of those laymen can understand what you've explained, then we have problems. You might propose that your area of study is simply way over our heads. But, then, I might propose that your own understanding is insufficient to explain the relevancy of your studies.