Well, to quote the article, you can see things like "p is absolutely continuous with respect to the Lebesque measure on En" and hundreds of variable names and sub/superscripts, none of which are intuitively named. It's really hard to argue that anyone who is not in academia would understand this without passing through it multiple times.

That being said, I think mathematicians should be perfectly permitted to do this, seeing as most people who read their papers are themselves, mathematicians. Thus spelling out every dumb detail would probably just be a waste of their time for the one case that the brave soul who is a programmer tries to decipher it.