The author didn't know radio waves travel at the speed of light. So he made some good-sounding intro based on incorrect assumptions (which made the whole intro a little cringe) which they apologized for. Yeah, shouldn't happen, but we're all human, we make mistakes.

You know that if you go deep down enough, everything is maths? Does it mean everyone should have a maths degree to do anything? Technology isn't science, technology is practical application of science. So you need to be a scientist to design such technology, but you "only" need to understand the high-level to convey to people how it works, because no one* is really interested in how it works.

* That's a hyperbole, I don't mean "no one" literally, you sound like the type of person that would reply with "muh, not no one", so I'm clarifying in advance¨

I hope you remember this reply of mine every time you make any mistake. Or any time you don't know something you should know because you for whatever reason missed it (which, again, happens to all of us).