Here's the context for my argument: believe it or not, there are people that will use language to impress or intimidate or to even mask their ignorance, even people who also purport to communicate ideas. Sometimes those people will also purposely use jargon with the aim to do both: direct their message to their in-group and purposely exclude individuals not from their in-group (I can list some examples of groups that do that, but I prefer not to go down that rabbit hole. I'm sure you can come up with some examples as well).
On the other hand, people who genuinely care about communicating ideas as broadly as possible will tailor their speech in such a way as to make it most accessible to as much of the audience as possible, because to them the idea is the important part not the medium. I leave it up to you to define 'accessible speech', but to pg it means communicating with simpler language - I think he makes a reasonable argument. Especially in context of a multicultural society with a sizable (recent) immigrant base and a global audience with various levels of English vocabulary knowledge.
It is also the hallmark of a good teacher when they can tailor the idea to a student who is smart enough to understand it but struggles with overcoming some kind of barrier (from vocabulary, to culture)
Secondly implicit in that argument is the notion that ordinary people can only comprehend 'simple speech' and have no appreciation for form or aesthetics, which is pretty arrogant but par for the course for your average PG essay and captures perfectly the stereotypical software developer developer mindset of completely lacking appreciation for style and thinking one's own ideas are so brilliant they have to be dumbed down for everyone else.