Part of this is because most mathematics is written for mathematicians, certainly not for non-engineers. Another hard part is that the concepts in mathematics are so abstract, and so unprecedented, that "reasonable" words that could be interpreted by non-technical people simply don't exist. This is even true in basic calculus. What is a reasonable name for "the function that describes the slope of another function at every point"? Keep in mind that you have to use that word over and over again for the next 1k pages of the thing you're writing, build up 50-100 other definitions recursively on top of it, and make sure it's relevant for all possible uses of the concept in the future of humanity, even uses that we today cannot possibly conceive.
You might reasonably say, "This is all the more reason to spend a lot of time thinking of a good name!" While everyone else actually doing math would say, "I need to get my work done, so let's just pick a name and get on with it." When math is done right, the concept in your head is concrete and ingrained enough that the particular word your using isn't that important.
That being said, having done math research and software engineering, mathematicians do spend about as much time as software engineers naming things. It's just easier for software engineers.