I don't think we need to postulate about aliens to come to a similar scenario. If someone in primary school, an undergraduate, or a practitioner asks me a ques

I don't think we need to postulate about aliens to come to a similar scenario. If someone in primary school, an undergraduate, or a practitioner asks me a question and I continue to lose them because I am unwilling to revise my explanation to something suitable for them, then, yes, I am elitist. That's not to say that I can't write something incredibly high level that only specialists in my field will readily understand. Frankly, I don't start my papers by telling the readers that we will be using Zermelo–Fraenkel set theory before going off and proving something about differential equations even though I likely depend on these results in order to get things like the real numbers. However, I don't think that's where the frustration is. I believe the frustration is that there is a dismissive attitude toward others when they don't understand the results. This is elitism. I also think there's a general unwillingness to self-reflect and consider that maybe the problem isn't that everyone else isn't educated enough to understand the results and maybe I'm just a terrible writer. For me, I'm about a decade out from my PhD and I've been working in my chosen field for almost two decades. As I've matured in my understanding of the material I actually write quite a bit more because I realize more closely that there are lots of little details that are really important and it's highly unlikely that only outside of a select few will pick up on that. Now, that is my choice and others can choose differently, but just because someone masters a field doesn't automatically mean that they can just skip the details.