Good read!
That said, I don't know about self-mockery. A good line from the linked lecture transcript:
> The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague.
He seems to be addressing the issue of inflated egos influencing people to be "real programmers". For example, do you use a simple GUI interface? -- HA! I can type an arcane string into a command line with my TOES! Clearly, I art teh superior to thou. Which is stupid, because a proper GUI that shows the full scope of the API is awesome, while memorizing arcane strings is a silly practice. But, some folks let feelings of intellectual superiority cloud their judgement and beliefs, which Dijkstra was speaking out against.
He repeats this theme several times, with the overall lecture being a tad repetitive and redundant as it states the same thing over and over in a repetitive series of repetitions, but for a specific example:
> Finally, although the subject is not a pleasant one, I must mention PL/1, a programming language for which the defining documentation is of a frightening size and complexity. Using PL/1 must be like flying a plane with 7000 buttons, switches and handles to manipulate in the cockpit. I absolutely fail to see how we can keep our growing programs firmly within our intellectual grip when by its sheer baroqueness the programming language —our basic tool, mind you!— already escapes our intellectual control. And if I have to describe the influence PL/1 can have on its users, the closest metaphor that comes to my mind is that of a drug.
In short, Dijkstra strongly advocates intellectual minimalism. The "humility" he advocates is fortitude against ego-driven peacockery in decision-making; taking the simplest possible approach, that's the easiest to do, even when doing so doesn't show off one's intellect.