If it wasn't simple, there would be more lines of code to implement the same idea. As it is, he might have had to spend an hour understanding one line to understand that idea (1 line/hr slow), as opposed to spending an hour reading a hundred lines of code (100 line/hr fast) for the same result.

kind of the flip side of pascal's "I would have written a shorter letter, but I did not have the time." if someone does have the time to make the letter short, it'll take longer to read (where "read" means to grasp the subtleties of.)