Tiny (or not...) yapping about Zim and functions PAK :P
If you think about it, he never actually aimed to cause harm; his programming is canonically broken/defective (plus he’s hyperactive, naive, chaotic, which is pretty obvious), and he’s just too... ambitious. You know, like those kids from the category of: "Oh, I can do this better and help out more!!" when they are asked to do a small chore like... put a pair of socks into the laundry basket. They decide to “help with the laundry” and start the washing machine, adding too much detergent — foam comes out of the hatch, and water spills all over the floor.
I like to think that because of his defective, he is on the level of—or rather, is just an ordinary young/minor Irken like of an Earth child. Hyperactive, childishly foolish behavior, believing every word from "authorities," and giving in to his whimsical ideas. He’s just... like an unsupervised kid without a proper upbringing, yk???
Unlike other Irkens who don't have a defect, their programming is hardwired into their brains, working exactly as intended, turning them into the ideal soldiers bred by the Empire in capsule, Despite their young age, brains are programmed to skip this part of ‘upbringing’ and ‘psychological development’, you see? The entire history of the Irk and knowledge are loaded into them, as if replacing the experience that they could gain for a long time in the process of growth and development, and besides, this makes the concept of Empire more militaristic. Why wait for soldiers to grow when you can train them as soon as they learn to stand?
In the comic where he faced his adult(!!!) version from the future, he was more than just... calmed down, but at the same time, he was still funny and Zim-like, just grown-up, serious, stability and successful.
That's because he got older, slowly, making mistakes and learning from mistakes, gaining experience! in general, he has gone through the standard path of development and growth, having achieved, so to speak, competence, it sounds logical, doesn't it?
That's why I truly think the PAK and the program inside it simply... mm, accelerated maturation, and it not a necessity, but a surgical intervention to optimize the Irken army, it sounds gloomy, but in the style of a show!
The PAK is like a Petri dish with agar-agar; it creates a ready-made nutrient medium, and all that's left is to assign roles to the little aliens and have them complete training for those positions—and boom, the perfect soldier is ready.